Video delivery systems using wireless cameras

ABSTRACT

A wearable form factor wireless camera may include an image sensor, coupled to an infrared detection module, which captures infrared video. The wearable form factor wireless camera may attach to clothing worn on a user and be ruggedized. A storage device may store the captured infrared video at a first fidelity. The stored infrared video may be capable of being transmitted at the first fidelity and at a second fidelity, with the first fidelity providing a higher frame rate than the second fidelity. A burst transmission unit may transmit the stored infrared video at the second fidelity via a cellular network. The infrared detection module, the image sensor, the storage device and the burst transmission unit may be powered by a battery. The image sensor, the infrared detection module, the battery, the storage device and the burst transmission unit may be internal to the wearable form factor wireless camera.

CROSS-REFERENCE TO RELATED APPLICATIONS AND CLAIM OF PRIORITY

This application is a continuation of U.S. patent application Ser. No.16/850,502 filed Apr. 16, 2020, which issued on Nov. 2, 2021 as U.S.Pat. No. 11,165,995, which is a continuation of U.S. patent applicationSer. No. 15/052,677 filed Feb. 24, 2016, which issued on Jun. 16, 2020as U.S. Pat. No. 10,687,028, which is a continuation of U.S. patentapplication Ser. No. 12/359,259 filed Jan. 23, 2009, which issued onMar. 8, 2016 as U.S. Pat. No. 9,282,297, which claims the benefit ofU.S. Provisional Application No. 61/023,369 entitled “VIDEO DELIVERYSYSTEMS USING WIRELESS NETWORK CAMERAS” and filed on Jan. 24, 2008,which are incorporated by reference as part of the disclosure of thisdocument.

BACKGROUND

This document relates to video delivery systems and techniques usingwireless cameras.

Network camera systems can be based on the Internet Protocol (IP) anduse Ethernet based networking technology. In some applications, networkcamera systems are replacing analog closed circuit television (CCTV) dueto various factors, such as accessibility, ease-of-use, cablingscalability, and lower cost of deployment and operation. With theubiquity of wireless networks such as WiFi networks, e.g., based on IEEE802.11 standards, and the emerging WiMAX networks, e.g., based on IEEE802.16 standards, wireless network camera systems are gaining popularityand are expected to become the dominant platform for video surveillanceapplications.

In an IP surveillance environment, the network camera system can includeIP cameras connected via twisted pair cabling to a network switch.Alternatively, the network connection can be achieved using wirelesslocal area networking (LAN) technology; e.g., the IEEE 802.11b standard.In various applications, IP cameras can include a web-server capabilityand remote clients or observers connected to the camera via standardTCP/IP interface standards such as FTP or HTTP. IP based network camerasystems can be designed using commercial off-the-shelf (COTS) componentsfrom a diverse number of suppliers.

SUMMARY

This document describes various aspects relating to video deliverysystems using wireless cameras and methods of providing such systems.

Systems, apparatuses, and techniques for video delivery can include oneor more of the following: a wireless camera arranged in a wearable formfactor including a battery to provide energy, and configured to generatea video feed, and a base station in wireless communication with thewireless camera and configured to receive the video feed from thewireless camera and process the video feed, and a video portal devicecommunicatively coupled with the base station and configured to receivethe processed video feed from the base station and deliver at least aportion of the processed video feed to one or more remote clients.

Systems, apparatuses, and techniques for video delivery can include awireless camera arranged in a wearable form factor including a batteryto provide energy and a base station in wireless communication with thewireless camera. The wireless camera can be configured to generate avideo feed, operate a first radio to transmit at least a portion of thevideo feed over a first wireless channel, and operate a second radio ina polling mode to receive information over a second wireless channel.The base station can be configured to receive the video feed from thewireless camera. The base station can reserve the first wireless channelfor the wireless camera by transmitting on the first wireless channel,wherein the base station transmits information to the wireless cameraover the second wireless channel to instruct the wireless camera totransmit on the first wireless channel at a known time. The base stationcan be configured to process the video feed and deliver the processedvideo feed to a video portal for remote viewing of the video feed.

These, and other aspects, can include one or more of the followingfeatures. The base station can be configured to detect an availabilityof a wireless channel using a carrier sense multiple access/collisionavoidance (CSMA/CA) protocol, transmit a wireless signal to asurrounding node within wireless range of the base station to cause thesurrounding node to remain silent on the wireless channel, transmit asignaling message signaling the availability of the wireless channel tothe wireless camera to cause the wireless camera to respond with awireless video data message including at least a portion of the videofeed. A size of the wireless video data message can be greater than asize of the signaling message, e.g., by at least a ratio of 100 to 1.Systems can include a vehicle to house one or more base stations.

The wireless camera can include a first radio to transmit at least aportion of the video feed to the base station over a first wirelesschannel, and a second radio that uses a polling mode to receiveinformation from the base station over a second wireless channel. Thewireless camera can include a burst transmission unit to transmitinformation, corresponding to burst periods, to the base station,wherein the burst transmission unit generates orthogonal frequencydivision modulation (OFDM) transmission symbols. The burst transmissionunit generates the transmission symbols corresponding to one of 24 Mbps,36 Mbps, 48 Mbps, 54 Mbps, and 65 Mbps data rates. The bursttransmission unit can generate the transmission symbols corresponding toa data rate that exceeds 22 Mbps. The burst transmission unit of thewireless camera can include multiple output circuits with respectivedifferent power amplifier bias settings. Each of the output circuits caninclude a power amplifier and antenna matching circuitry. The bursttransmission unit can be configured to select one of the output circuitsfor data transmission based a wireless link condition. The base stationcan reserve the first wireless channel for the wireless camera bytransmitting on the first wireless channel. The base station cantransmit information to the wireless camera over the second wirelesschannel to instruct the wireless camera to transmit on the firstwireless channel at a known time. The wireless camera can include a usercontrol to indicate an event of interest to the base station. The videoportal device can access the wireless camera, wherein the wirelesscamera generates a user alert based on the access. The wireless cameracan include a capacitor holding circuit to increase battery life whileallowing for current surges when transmitting to the base station. Thesecond radio of the wireless camera can include a direct-sequence spreadspectrum (DSSS) receiver. The second radio in the wireless camera can beconfigured to operate continuously for periods of time exceeding fivehours while drawing less than 50 microwatts in average power.

Systems, apparatuses, and techniques for video delivery can include awireless camera node that includes an image sensor for capturing videoand a base station to operate a transceiver, detect an availability of awireless channel using a carrier sense multiple access/collisionavoidance (CSMA/CA) protocol, transmit a wireless signal to asurrounding node within wireless range of the base station to cause thesurrounding node to remain silent on the wireless channel, transmit asignaling message signaling the availability of the wireless channel tothe wireless camera node to cause the wireless camera node to respondwith a wireless video data message. The base station can be configuredto receive and process video from the wireless camera node for remoteviewing.

These, and other aspects, can include one or more of the followingfeatures. In some implementations, the CSMA/CA protocol is based on a802.11 standard. A size of the wireless video data message can begreater than a size of the signaling message, e.g., by at least a ratioof 100 to 1. The wireless camera node is configured to operate areceiver capable of receiving the signaling message for one or moreperiods of time averaging less than 5% of elapsed time during extendedperiods of video transmission. The wireless camera node can use a 2.4GHz radio spectrum to transmit the wireless video data message. Thewireless camera node can use Orthogonal Frequency Domain Modulation(OFDM) to transmit the wireless video data message. The wireless cameranode can be powered by sources such as a battery or solar power. Thewireless camera node can be arranged in a wearable form factor and canweigh less than 100 grams, or less than 50 grams.

A wireless camera can include an image sensor for capturing video, afirst radio to transmit video to a base station over a wireless channel,wherein the base station is configured to reserve the wireless channelby transmitting on the wireless channel, a second radio to receivecommunications from the base station and a controller in communicationwith the image sensor, the first radio, and the second radio, whereinthe controller is configured to operate the first radio to transmit avideo feed to the base station in response to receiving the signalingmessage. The second radio of the wireless camera can be configured tooperate in a polling mode to receive a signaling message signaling anavailability of the wireless channel.

Systems, apparatuses, and techniques for video delivery can includeobtaining video from one or more battery powered and wearable wirelesscameras, each of the one or more battery powered wireless camerasincluding an internal battery to provide energy; transmitting theobtained video to a base station that is separated from the one or morewireless cameras and in wireless communication with the one or morewireless cameras; processing the obtained video in the base station; andtransmitting the processed video for remote reviewing.

These, and other aspects, can include one or more of the followingfeatures. Implementations can include charging a remote client foraccessing the video portal to watch video from the one or more wirelesscameras. Transmitting the processed video to a video portal can includetransmitting the processed video over a wireless network.Implementations can include receiving a command from the video portal toaccess one of the wireless cameras. Implementations can includeoperating the accessed wireless camera to generate an alert to notify auser of the video portal's access. Implementations can includetransmitting a message on a wireless channel to reserve the wirelesschannel for transmission of the obtained video. The message can includeclear-to-send (CTS)/self signaling information. Transmitting theprocessed video for remote reviewing can include transmitting theprocessed video to a video portal.

The systems and techniques described herein can provide wireless IPvideo systems that require no power cable and can potentially operate onstandard off-the-shelf battery solutions for over a year. In addition,the systems and techniques described herein can resolve theinterference, interoperability and reliability problems currentlyassociated with existing wireless camera systems. Video delivery systemscan be provided by using low-cost, battery-powered, and wearablewireless cameras connected to a base station, such as a video hub orvideo engine. In addition, a video portal device can connect with one ormore base stations and function as a video hosting server that allowsfor multiple remote viewing through one or more wireless cameras.

The subject matter described in this specification can be embodied in asystem that includes a battery powered wireless camera including aninternal battery to provide energy and a burst transmission unit totransmit information corresponding to burst periods. The system alsoincludes a base station, separated from the battery powered wirelesscamera, in wireless communication with the battery powered wirelesscamera to receive information from the battery powered wireless camera.The base station is configured to process the received information andincludes a web server to relay the processed information to a client.Other embodiments of this aspect include corresponding methods,apparatus, and computer program products.

The subject matter described in this specification can be embodied in awireless camera system which includes a battery powered wireless cameraincluding an internal battery to provide energy and a burst transmissionunit to transmit information corresponding to burst periods. The systemalso includes a base station, separated from the battery poweredwireless camera, in wireless communication with the battery poweredwireless camera to receive information from the battery powered wirelesscamera. The base station is configured to process the receivedinformation and including a web server to relay the processedinformation to a client, and the base station is powered by a powercable connected to an external power source. The burst periods aredetermined based on at least one of a wireless link channel averagebandwidth capacity, a fidelity of images transmitted, and a latency ofestablishing and tearing down a wireless connection between the batterypowered wireless camera and the base station.

The subject matter described in this specification can be embodied in asystem that includes a base station which includes a first receiverconfigured to receive information in a first wireless network and asecond transmitter configured to transmit information in a secondwireless network. The system also includes a remote node which includesa first transmitter configured to transmit information in the firstwireless network and a second receiver configured to receive informationin the second wireless network. The second transmitter is furtherconfigured to transmit control information from the base station to theremote node via the second wireless network and the first transmitter isfurther configured to transmit compressed video information from theremote node to the base station via the first wireless network.Additionally, the second receiver in the remote node is furtherconfigured to operate for substantially longer period of time than thefirst transmitter in the remote node.

The subject matter described in this specification can be embodied in amethod that includes transmitting information, by one or more batterypowered wireless cameras having internal batteries in a wireless link.The transmitting of information corresponding to burst periods. Themethod also includes receiving information by a base station, and thebase station includes a web server. The method further includesprocessing the received information in the base station, and relaying,by the web server, the processed information to a client.

In another aspect, a wireless camera system includes a battery poweredwireless camera having an internal battery to provide energy and a bursttransmission unit to transmit information corresponding to burstperiods. The system also includes a base station, separated from thebattery powered wireless camera, in wireless communication with thebattery powered wireless camera to receive information from the batterypowered wireless camera. The base station is configured to process thereceived information and the burst periods are determined based on atleast one of a wireless link channel average bandwidth capacity, afidelity of images transmitted, and a latency of establishing andtearing down a wireless connection between the battery powered wirelesscamera and the base station.

In a further aspect, a wireless camera system includes a solar poweredwireless camera that includes at least one solar cell. The system alsoincludes a base station, separated from the solar powered wirelesscamera, in wireless communication with the solar powered wireless cameraand configured to receive information from the solar powered wirelesscamera. The base station is further configured to process the receivedinformation and includes a web server to relay the processed informationto a client.

In one aspect, a wireless camera system includes a battery poweredwireless camera that includes a power unit for energy source and a bursttransmission unit to transmit information corresponding to burstperiods. The system also includes means for determining the burstperiods for transmission of information. The system further includes abase station configured to receive information from the battery poweredwireless camera and to process the received information. The basestation includes a web server to relay the processed information to aclient. The system additionally includes a first wireless linkconfigured to connect the battery powered wireless camera and the basestation.

In another aspect, a network camera includes a networking moduleconfigured to communicate with a network. The network camera alsoincludes an image capturing module configured to capture images. Thenetwork camera further includes an image compression circuit configuredto compress the captured images. The network camera additionallyincludes a privacy lens cap or a visible shutter configured to enhanceprivacy and prevent the image capturing module from capturing images.The network camera can be a wired or a battery powered wireless camerathat includes an internal battery.

In yet another aspect, a network camera includes a burst transmissionunit configured to transmit information corresponding to burst periodsand a networking module configured to communicate with a network. Thenetwork camera also includes an image capturing module configured tocapture images. The network camera further includes an image compressioncircuit configured to compress the captured images. The network cameraadditionally includes a privacy lens cap or a visible shutter configuredto enhance privacy and prevent the image capturing module from capturingimages. The network camera can be a wired or a battery powered wirelesscamera that includes an internal battery.

These and other embodiments can optionally include one or more of thefollowing features. For example, a plurality of cameras can beassociated with one base station. A plurality of cameras can beassociated with two base stations to provide redundancy in case one ofthe base stations fails. Furthermore, a plurality of cameras can beassociated with a plurality of base stations in a mesh architecture tomaximize redundancy, resiliency and low power operation. The internalbattery can be configured to provide energy without a power cableconnected to an external power source that is external to the camera.

The base station configured to receive information from the one or morebattery powered wireless cameras can include scanning one or morecommunication channels for channel availability between the base stationand the one or more battery powered wireless cameras; obtaining anavailable channel for data transmission based on the scanning of channelavailability; and associating the available channel with a specific oneof the one or more battery powered wireless cameras. The associating ofthe available channel can include reserving the available channel for apredetermined period of time, and assigning the reserved availablechannel to the specific one of the one or more battery powered wirelesscameras. In addition, during the predetermined period of time, theavailable channel can appear to the other one or more battery poweredwireless cameras as unavailable for wireless communication.

Each of the one or more battery powered wireless cameras can include ascanning circuitry configured to scan the one or more communicationchannels for channel availability and to determine available channelsfor data transmission. Each of the one or more battery powered wirelesscameras can also include a storage device configured to store data whenthere are no available channels for data transmission. The wirelessnetwork camera system can also include a network connecting the basestation and the client, and the client can include a video surveillanceapplication to display video images. The network can be one of a wiredEthernet network, or a wireless network such as a WiFi network or aWiMAX network. The transmitted information can include compressed videosignals or digitally encoded video signals.

Each of the one or more battery powered wireless cameras can include animage sensor configured to produce an image; an image compressioncircuit configured to compress a digital file of the image produced bythe image sensor; and a substrate configured to monolithically integratethe image sensor and the image compression circuit. The burst periodscan be determined based on at least one of a wireless link channelaverage bandwidth capacity, the fidelity of images transmitted, and alatency of establishing and tearing down the wireless link. The burstperiods can be further determined based on a trigger event caused by oneof a sound detection, an infrared motion detection, an ultrasonicdetection, a radio signaling circuitry, and a channel availability fordata transmission.

The wireless network camera system can include a first wireless networkconfigured to communicate between the one or more wireless cameras andthe base station via one or more high-bandwidth channels. The wirelessnetwork camera system can also include a second wireless networkconfigured to communicate between the one or more wireless cameras andthe base station via one or more low-bandwidth channels. The secondwireless network can be configured to be more reliable and/or moreavailable (e.g., operates for a longer period of time) than the firstwireless network.

Both the first and second wireless networks can be one of a wirelessEthernet network, a WiFi network, and a WiMAX network. In addition, boththe first and the second wireless networks can be based on Multiple InMultiple Out (MIMO) technology. The second wireless network can beconfigured to operate for an extended period of time to facilitate oneor more of set-up, installation, and troubleshooting activities. Thesecond wireless network can also be used to signal to the one or morewireless cameras that one of the one or more high-bandwidth channels isavailable for data transmission. The channel availability information ofthe one or more high-bandwidth channels can be determined by processingin the base station.

The base station can include a transmitter configured to transmit viathe second wireless network information that includes one or more ofpositional, zoom, and tilt commands to each of the one or more wirelesscameras. The base station can also include a transmitter configured totransmit via the second wireless network a command to flush informationand data stored on each of the one or more wireless camera through thefirst wireless network. Each of the one or more battery powered wirelesscameras can include a high-bandwidth transceiver and a low-bandwidthtransceiver.

The high-bandwidth transceiver can be configured to receive informationvia the first wireless network and the low-bandwidth transceiver can beconfigured to receive information via the second wireless network. Thelow-bandwidth transceiver can be configured to consume less than 4 mW ofpower in constant operation or operate in a polling mode that reduces anaverage energy consumption of the camera. The base station can includetiming circuits configured to be synchronized with the cycle of thepolling mode in the receiver.

Each of the one or more battery powered wireless cameras can include astorage device configured to store the information at a first fidelity.The information can be transmitted to the base station at a secondfidelity, and the first fidelity is different from the second fidelity.The one or more wireless cameras can be configured to be powered up toobtain information in response to a trigger event caused by one of asound detection, an infrared motion detection, an ultrasonic detection,a video processing based movement detection, a relay switch, a microswitch, and a radio signaling circuitry. Each of the one or morewireless cameras can further include a storage device configured tostore captured information for a predetermined period of time. Thestored captured information can be transmitted to the base station inresponse to a trigger event.

Each of the one or more wireless cameras can include a first switchconfigured to control one or more of operation in darkness, operationbased on sound detection, operation based on infrared motion detection,operation based on ultrasonic detection, and operation by triggers; anda second switch configured to indicate operation duration of the one ormore wireless cameras. A frame rate can be obtained based on theoperation duration so that the internal battery can last substantiallyfor the operational duration indicated by the switch.

Each of the one or more battery powered wireless cameras can furtherinclude an uncompressed image capture module configured to operate basedon periods that are different from the burst periods. The image capturerate and the burst transmission rate can be based on motion detection,and further wherein when motion is detected in the captured images, theimage capture frame rate is increased, and when motion is not detectedin the captured images, the image capture frame rate is decreased.

The internal battery of the wireless camera can be based on one or moreof solar cells, fuel cells, galvanic cells, flow cells, kinetic powergenerators, and environmental energy sources. The internal batteryoutput voltage can be boosted or regulated by an active power managementcircuitry. The internal battery can be recharged by one or more of solarcells, fuel cells, galvanic cells, flow cells, kinetic power generators,and environmental energy sources. The internal battery can include anarray of rechargeable battery cells configured to extend the useablelifetime of the rechargeable array to be greater than a lifetime of asingle rechargeable battery cell, and less than the entire array ofrechargeable battery cells are used at a given time.

The useable lifetime of the internal battery can be extended bycontrolling the current withdrawal of the rechargeable battery cells towithin a predetermined current limit. The controlling of currentwithdrawal from the internal battery can be performed through a highefficiency regulation circuit that includes a switching regulator fordrawing a limited current flow from the battery cells, and a capacitorfor temporary storage of energy. The internal battery can be replaced bya high capacity capacitor and a charging circuitry associated with thecapacitor. The internal battery can include at least a high capacitycapacitor and a rechargeable battery.

Each of the one or more battery powered wireless cameras can include acompression module configured to operate based on periods that aredifferent from the burst periods. Each of the one or more batterypowered wireless cameras can capture and transmit audio information andsensor information. Each of the one or more battery powered wirelesscameras can be surface mountable and can include a housing that has asolar panel configured to recharge the internal battery.

Particular aspects can be implemented to realize one or more of thefollowing potential advantages. A fundamental architectural change inthe wireless camera can be implemented to obtain significant powersavings in wireless network camera systems. Such fundamental change canoffer substantial power savings over commonly understood power-reducingtechniques such as using more efficient electronic components in theradio transceivers, image capture, and compression integrated circuits.

An ultra-low power wireless camera can be obtained without compromisingthe ability of new and existing client system to access data usingstandard IP connections and standard or de-facto application programminginterfaces (APIs). In particular, the base station code can comply withwell established IP camera API's. Additionally, even though the wirelesscamera can operate at an ultra-low average power, during the burstperiod when the camera is transmitting data to the base station, thecamera can allow for power consumption in excess of 100 mW. This is incontrast to existing wireless sensors which will typically consume lessthan 100 mW of power when transmitting data.

Multiple wireless cameras (e.g., up to 16 wireless cameras) can beassigned to a single base station. The base station and wireless cameracombination can deliver all the intelligence and features expected for acommercial grade IP camera solution. The solution integrates intoexisting IP networks and exposes standard video monitoring applicationinterfaces so that popular video surveillance data applications can beused. This makes for rapid, seamless and pain free deployment. From thenetwork perspective, the combo processing ensures that all wirelesscameras appear to be 100% compatible IP cameras. Video can be deliveredcompressed to industry standard format such as MJPEG or MPEG-4, ready tobe accessed and managed by industry standard software.

The base station can connect to a regular wired Ethernet LAN and on tothe Internet, just like any IP surveillance system. A seamlessintegration can occur over a standard 802.11b/g/n wireless Ethernetnetwork. Since it can be wireless to the Internet access point, thedistance range of the wireless network camera system can be as wide astoday's wireless systems. The user can perform a walk-through wizardonce, and begin installing multiple security cameras anywhere within therange of the base station.

Further, a battery powered wireless camera operation can be achievedusing well established components. Battery powered wireless networkcamera systems can be achieved without additional external power sourceor cabling. These systems can have standard web server capability forclient access to the captured data. Because no power cabling is needed,these battery powered wireless network camera systems can be deployed inlocations where previously difficult to service. Camera operation forextended periods of time can be obtained using small battery packs.

By using modified media access techniques, unreliable or inconsistentconnectivity associated with the standard IEEE 802.11 wireless links canbe avoided. Additionally, the erratic set-up and/or operation of awireless link due to interference or other environmental factors can beminimized. The drawbacks of the IEEE 802.11 MAC standards in poorconnection conditions can be overcome by observing interference and alsousing techniques to reserve and hold a connection for data transmission.For example, by implementing a second low-bandwidth radio/transceiver inthe wireless camera, the modified media access techniques can betriggered and controlled through the second radio. The low-bandwidthradio can establish a link in conditions where the high-bandwidthradio/transceiver cannot.

By incorporating more functionality in the base station of the wirelessnetwork camera system, the base station can detect and correct linkproblems by requesting retransmission of the captured data. Such requestcan be sent via the low-bandwidth radio which can be more reliable anduse lower power than the high-bandwidth radio. This retransmission canbe hidden and transparent to the client surveillance application throughthe virtual web server or relay server in the base station. In addition,image and video analytical functions such as object recognition, peoplecounting, and license recognition can be implemented in the base stationrather than the camera. These analytical functions can be implemented ina hidden way so that it logically appears to the client that thesefunctions are occurring in the camera. Furthermore, in applicationswhere privacy of the image or audio data needs to be protected, the datatransmitted wirelessly can be encrypted.

A wearable form factor wireless camera may include an image sensor forcapturing video, the image sensor powered by a battery internal to thewearable form factor wireless camera. The camera may be ruggedized andattached attach to clothing worn on a user. Further, the camera mayinclude a burst transmission unit to transmit video via a cellularnetwork, and include video analytics software executed by an internalprocessor, coupled to a buffering memory and powered by the battery. Thecamera may also include an internal storage device powered by thebattery and configured to store video information at a first fidelity,the stored video information capable of being transmitted to a basestation at the first fidelity and at a second fidelity. Also, the firstfidelity may provide higher video quality than the second fidelity.

Further, the burst transmission unit may transmit stored videoinformation at the second fidelity. Also, the video analytics software,executed by the processor operating with the buffering memory andpowered by the battery, may switch the burst transmission unit fromtransmission of video at the second fidelity to transmission of video atthe first fidelity upon an occurrence of a trigger event. Accordingly,the burst transmission unit may transmit stored video information at thefirst fidelity.

In another example, a wearable form factor wireless camera may includean image sensor which captures infrared video. The image sensor may becoupled to an infrared detection module. Both the infrared detectionmodule and the image sensor may be powered by a battery. The imagesensor, the infrared detection module and the battery may be internal tothe wearable form factor wireless camera. Further the wearable formfactor wireless camera may attach to clothing worn on a user and beruggedized. A storage device may store the captured infrared video at afirst fidelity, be powered by the battery and be internal to thewearable form factor wireless camera. Also, the stored infrared videomay be capable of being transmitted at the first fidelity and at asecond fidelity, with the first fidelity providing a higher frame ratethan the second fidelity. A burst transmission unit may transmit thestored infrared video at the second fidelity via a cellular network.Further, the burst transmission unit may be internal to the wearableform factor wireless camera.

In a further example, a processor, coupled to the storage device, abuffering memory and the burst transmission unit, and powered by thebattery, may switch the burst transmission unit from transmission of thestored infrared video at the second fidelity to transmission of thestored infrared video at the first fidelity upon an occurrence of atrigger event. Further, the processor and the buffering memory may beinternal to the wearable form factor wireless camera. Additionally, thetrigger event may include an infrared motion detection, a sounddetection, an ultrasonic detection, a relay switch, a micro switch,radio signaling circuitry or a user input. Also, the infrared detectionmodule may trigger the trigger event.

In an additional example, the infrared detection module may include apyroelectric infrared sensor. Moreover, the infrared detection modulemay include a passive infrared (PIR) detector. Also, the wearable formfactor wireless camera may pulse a highly efficient infrared lightemitting diode (LED) synchronized to an image capture frequency andphase. In addition, the burst transmission unit of the wearable formfactor wireless camera may comprise multiple output circuits withrespective different power amplifier bias settings, wherein each of theoutput circuits comprise a power amplifier and antenna matchingcircuitry. Additionally, the battery may be a low voltage hearing aidbattery. Further, the battery may power the wearable form factorwireless camera for eight or more hours. Also, the first fidelity mayprovide a frame rate of thirty (30) or more frames per second (fps).

These aspects may be implemented using a system, method, or a computerprogram product, or any combination of systems, methods, and computerprogram products. The details of one or more embodiments are set forthin the accompanying drawings and the description below. Other features,aspects, and advantages will be apparent from the description, thedrawings, and the claims.

DESCRIPTION OF DRAWINGS

FIG. 1A shows an example of a battery powered wireless camera.

FIG. 1B shows an example of a base station with a digital portalinterface.

FIG. 1C shows an example of a video delivery system.

FIG. 1D shows a different example of a video delivery system

FIG. 1E shows an example of a video base station and system.

FIGS. 2A, 2B show different examples of a battery powered wirelessnetwork camera system for remote surveillance applications.

FIG. 3 shows an example of transmission circuitry that includes multipleoutput circuits.

FIG. 4 shows an example of a burst data transmission.

FIG. 5A shows a flow chart example of a MAC algorithm.

FIG. 5B shows a flow chart example of a process that can be used toimplement the CTS-to-Self algorithm.

FIG. 5C shows an example of communications between a base station and awireless camera.

FIG. 6 shows an example of current limiting circuitry.

FIGS. 7A, 7B show different examples of computing systems and devices.

Like reference symbols in the various drawings indicate like elements.

DETAILED DESCRIPTION

The systems and techniques described herein relate to providing videodelivery systems using low-cost, battery-powered, and wearable wirelesscameras connected to a base station, such as a video hub or a videoengine. In addition, a computer system such as a video portal device ora server configured with a video portal software suite can connect withthe base station and can function as a video hosting server that allowsfor multiple remote viewing through one or more wireless cameras.

A video delivery system can include one or more wireless cameras, a basestation (e.g., a video hub, video engine, access point), and a videoportal server or processing device configured to run a video portalsoftware suite. Wireless camera features may include low-cost hardware,battery-powered, and wearable aspects. For example, the wireless cameracan run on low voltage batteries, e.g., hearing aid batteries, andprovide power for eight hours or more including a full year of operationdepending on the form factor of the wireless camera. A wireless cameracan include a holding capacitor or similar circuitry to allow forcurrent surges without degrading the battery life when transmitting fromthe camera to a base station. In addition, such a holding capacitor orsimilar circuitry can allow smaller battery cells with lower peak powerdelivery capabilities to be used.

The wireless cameras can allow users to perform various functions, e.g.,functions that adjust or control a camera operation. User control forwireless cameras in a wearable form factor can include starttransmitting, stop transmitting, increase/decrease frame rate, zoomin/out, send signal to base station/video hub that an event of interestis occurring, and sending an alarm to the base station. A wearablewireless cameras can have a small form factor. Such a form factor caninclude a one touch button or one or more multifunction buttons. Awireless camera may be arranged in different form factors such asdifferent shapes and sizes and can include interchangeable ear pieceselements to make the wearable camera user more comfortable.

The systems and techniques described herein can allow a wearablewireless cameras to operate at a sustained basis of 30 frames per secondwith DVD quality, with transmitted power during data transmission ofaround 12 dBm, and with an average power consumption of less than 100 mWor even less than 50 mW. For these types of higher frame rates, usingcapacitor holding circuits, a few small hearing aid sized button sizedbattery cells can be used to allow the wearable camera to be active for8 hours or more. Additionally, for privacy measures, a highly visibleprivacy lens cap can be integrated on the wearable camera so that it isclear to people around the camera that the lens is obscured and cannotbe capturing useful video. Furthermore, in some implementations, thewearable camera can be powered by rechargeable batteries. Theserechargeable batteries can be recharged using inductive couplingtechniques, or through the use of a miniature USB-style connector.

The systems and techniques described herein can benefit many types ofactivities including law enforcement, military, paramedics, consumer,and sports. A wireless camera can include components for capturingimages, videos, series of images, and audio. Different types ofprofessionals such as law enforcement officers (LEOs), militarypersonnel, paramedics, and emergency response personnel may recordand/or transmit live audio and video of events in the field forsupervision of such events and/or liability mitigation of events in thefield.

The systems and techniques described herein can allow a wireless camerato be worn on a person without cables for power or data recording. Aperson may wear a wireless camera in one of many styles such as on theear (similar to a Bluetooth headset), on clothing such as a hat orhelmet, or attached to a shirt, jacket, or belt. In someimplementations, a wireless camera can be integrated into glasses,badge, radio microphone, ball point pen, tie pin, or button; or attachedto a gun or flashlight. Additional wireless cameras may be placed ondifferent people or equipment involved in an activity.

The systems and techniques can benefit different types of consumer usessuch as personal video or audio recording or live videotransmission/streaming to the Internet from a wireless camera worn by aperson. Examples of consumer uses include capturing video or images atfamily events or vacations (birthdays, sports games, parties,graduations, etc.), capturing action activities, streaming videofeedback from a wearable wireless camera to an Internet site such as asocial networking site, monitoring children, recording from a user'sview point for school projects, work projects, or proof of performancerequirement. Other uses are possible.

Sport based uses can include recording or transmitting live feeds ofaudio and video of sports games and activities from a player'sviewpoint. The systems and techniques can post the feeds to the Internetor recorded for future use. In sports such as vehicle and motor or pushbike racing, a wireless camera may be worn by a rider or driver andcommunicate a video feed to a base station placed at a convenientposition in relationship to the bike or vehicles. For sports such asskiing, snow boarding, skateboarding, or push bike riding, a user mayattach a wearable wireless camera to his clothes or equipment totransmit a video feed to a base station. The base station canre-transmit the video feed to a network such as the Internet. In somesporting events, a wireless camera may be attached to vehicles such as arace car, motorcycle, or boat. Other uses are possible.

A wireless camera can wirelessly communicate with a device such as avideo base station, mobile device or smartphone configured tocommunicate with the camera, to record, further transmit or broadcastvideo via a wireless air link such as WiFi or cellular network.Furthermore, a base station may be wearable or located in a secure placein proximity to a wireless camera (e.g., within a 1,000 meters or amile). In some implementations, a base station can be integrated into avehicle such as a LEO vehicle, military vehicle, or ambulance. The basestation can communicate with other base stations for sharing images orvideo. A video base station can manage one or more wireless cameras,e.g., on multiple users, devices, equipment, or combinations thereof.

A wireless camera operator may turn on or off the wireless camera orallow or disallow transmission of live video and audio. For example, aparamedic may enable his wireless camera to transmit video of thepatient while en route to a hospital. Medical personnel at the hospitalcan use a remote reviewer, such as a computer or mobile device, toreceive the video transmission so that medical personnel can viewinjuries and status of a patient during field treatment and transport sothat they are prepared for the patient's arrival. In a differentexample, players of a sports game may wear a wireless camera andtransmit play feed to games officials such as referees via a basestation. Referees can use a remote viewing device to connect to a basestation to download and review the play feed to make gamedeterminations.

A wearable wireless camera can include batteries such as AA, AAA, orhearing aid style batteries. A wireless camera can include arechargeable battery. In some implementations, a wireless camera canintegrate with a one-way or two-way audio link to a camera wearer. Forexample, if the wearable camera is implemented in the form of a“Bluetooth” style headset, the audio link can be implemented, and such alink could also be engineered to be somewhat private to the camerawearer. The wearable camera can include a microphone to capture audio.Such a microphone can be optimized to capture sound within the camera'sfield of view using well established techniques to localize and focusthe microphone's sensitivity. Acoustic noise shields can also beemployed to further enhance the audio channel quality.

In other implementations, a handheld remote control can wirelesslycommunicate with a base station or a wearable camera to control thecamera or base station functions, and allow remote operation of thevideo system. The base station can include video processing, featuresand adjustments that would normally be found in traditional videocamcorders. Information regarding these features can be transmitted tothe wearable camera via a communications link. For example, a videoprocessing, features, or adjustments operation can include view finder,optical or digital zoom, face detection, image stabilization, videoreview modes where previously stored video can be reviewed, videoediting operations, titling, video/special effects, face detection,digital of optical zoom, setting of aperture or shutter speed priority,white balance, resolution, frames per second, and auto focus modes ofoperation

Alerts such as “this camera is being actively accessed” can be sent byor thorough the base station/video hub to the wearable wireless camera.Such alerts might be manifested on the wearable camera using an audiolink or by a vibration of the wearable camera. A wireless camera canalso be developed to easily fit into or attach to various items ofclothing and jewelry such as: neck ties or bow ties, necklaces, hats,baseball caps, earrings, headpieces, sun glasses, jackets and similaritems. A wireless camera can accommodate snap-on colored or patternedcasings which can be swapped by the user for personal or appearancepreferences. A wireless camera can be ruggedized to allow use in wet andharsh weather conditions. A wireless camera can be sealed to withstandwater or chemical submersion. In certain implementation, A wirelesscamera can be integrated with a location-sensing capability using, e.g.,GPS or triangulation of wireless signals. In this manner, the videosystem can determine the approximate location of the wearable camera sothat the wearer can be located.

A base station can include a universal video hub that supports wirelesscameras, as well as legacy cameras (e.g., analog, or wired IP cameras).The base station can also have an optional LCD screen and keyboard toallow for a local viewing of the wireless cameras on the base station.In addition, the base station can include a video bandwidth shapingfunctionality, such as tiling of videos so that multiple video imagescan fit on a single screen, and reducing the resolution of the videoimages so that more video images can be delivered to the remote clients.The base station can also include an interface to a proprietary webportal, which is a proprietary link different from the standard HTTPlink. The base station can further include a web cam interface thatallows the wireless cameras to function as mobile or wireless web cams.Furthermore, the base station can include the video encoder so that theimages can be displayed, e.g., on an analog TV or on an HDTV. Thefunctionalities of the base station can also be integrated with aportable device, such as a cellular phone or a PDA, through acombination of software and hardware integration.

The base station can communicate with a video portal softwaresuite/device through a broadband wireless data or cellular network suchas broadband 3G, CDMA, EVDO, HSDPA or similar modem chipset implementedthrough a USB, PCI-Express or PCMCIA card interfaces. The base stationcan also implement video traffic shaping functions such as reducing thedata received form the cameras into a lower resolution video streambefore transferring the video feeds onto the Internet. Furthermore, thebase station can also process the video streams to exploit the limitedbandwidth into the Internet. For example, the base station can multiplexvarious video feeds into a tiled arrangement in one video so that endusers can view multiple cameras simultaneously on a single video feed.The base station can retain high quality recordings from all camerassimultaneously storing these recording on a local storage device such asa flash memory or a hard drive. These recording can be retrieved forfuture transmission, review, or editing.

A video portal device can serve as a video hosting server and can allowmultiple remote clients to view video feeds from the wireless cameras.In this manner, more bandwidth is provided for the video delivery systembecause only one upload is needed from the base station and images frommultiple wireless cameras can be aggregated at the video portal device.Furthermore, a video delivery system including a base station andseparate video portal device can increase system reliably because thevideo portal device can function as the “man in the middle” to avoidconnection problems associated with firewalls.

A video delivery system may provide multiple revenue sources. Forexample, the video delivery system can implement a live “micropay-per-view” event to allow remote clients an opportunity of viewing alive event through one or more wireless cameras. In addition, the videodelivery system can potentially draw a large audience into the videoportal and allow for advertising revenues such as pay per click.Furthermore, the video delivery system can be part of a mobile carrierservice by sharing a percentage of the subscription or data usagerevenue with the mobile carriers.

For example, the wireless network camera systems described herein canoperate for an extended period, e.g., months or even years withoutmaintenance in certain applications. By looking at the energyrequirements of the system over time, the systems and techniquesdescribed herein can use a time-sliced energy cycling technology todistribute processing over time and location. Furthermore, the systemsand techniques described herein can combined with modern, availablewireless technologies (such as the modulation schemes deployed insystems like WiFi 802.11) and off-the-shelf advanced semiconductorcomponents. As a result, an overall reduction in the camera power of twoor more orders of magnitude can be achieved. For example, the wirelesscamera described herein can potentially operate on less than 3 mW ofpower on a sustained basis, and the wireless camera can run over 12months using 8 AA Lithium batteries.

Connection from the base station to other IP security video cameras andnetwork can be done via wired or wireless links. Each wireless cameraconnected to the base station can be assigned an IP address from theEthernet router through the regular DHCP or other standard Ethernetmethods. Further, each wireless camera in the network behaves like aregular IP camera to any existing client or application on the LAN. Inthis way, each wireless camera can be addressable through industrystandard APIs so that each video stream and each wireless camera can beviewed, recorded, and manipulated individually without any modificationsto existing applications and hardware.

Numerous applications, such as alarm verification and surveillanceapplications for constructions sites, mobile transportation, and borderpatrol may use the wireless network camera systems described herein

Construction Sites

Construction theft is widespread and nothing new, but the amount oftheft is increasing. Construction thefts, which are rarely solved, canlead to construction delay, higher costs and insurance rates, and higherhome prices. The National Association of Home Builders estimates thatthe construction theft problem costs the US building industry $4 billionannually and increases the cost of the average home by 1.5 percent. Somebuilders try to protect themselves by using bind tools and materialsinto heavy heaps or block driveways. Most install temporary locks onwindows and doors and wait until the last minute to install appliances.

Installing traditional video security cameras can be difficult becausepower is unlikely to be available at the location best served by thevideo camera. Most builders are unwilling to invest the dollars for atemporary installation. In addition, cabling for a network camera systemcan be impractical at the construction site. The wireless network camerasystems described herein can offer a solution to this problem. Wirelesscameras can be quickly added and moved during the construction phase,and theft activity can be identified in real-time. Since the cameras aretemporary, the builder can re-use the cameras at other new constructionsite, decreasing the initial investment for a total security system tocover all construction projects.

Mobile Transportation

Without proper measures, public transit vehicles, school buses, lightrail cars, and trains can be affected by security issues involvingpassengers and operators. Problems such as vandalism, assault and evensuspicious liability claims can affect or disrupt an operation. Whilethere are mobile surveillance systems, they require an on-board DVRwhich can be cumbersome and difficult to retrofit into an existingtransportation vehicle. In addition, the existing system may not providereal-time information to a central monitoring station. The wirelessnetwork camera systems described herein can alleviate this problem witha low installation cost, and very little additional equipment toinstall.

With protected dome cameras at multiple locations on the transportationvehicle, a broad coverage can be enabled, while providing an avenue forcentral monitoring through a 3G IP based data network. The base stationcan store images temporarily should an interruption occur through the 3Gnetwork preventing immediately transfer of images. With the temporarystorage at the base station, a near real-time video security monitoringcan still be obtained with a very cost effective system. Video recordingcan be done at the central location, providing the benefits of immediateaccess to security officials, elimination of daily video transfer forhistorical recordkeeping and leveraging lower storage costs at thecentral facility.

Military and Border Patrol

In a war zone, there is no time and too much risk to install videosurveillance systems. In terms of security, there is no greater needthan in military applications for quick, reliable and secure mobilevideo security systems that can be centrally monitored. Lives can besaved in identifying rogue activity and quickly responding topotentially dangerous scenarios before an enemy can act. In most regionsof interest, there is no power availability and the lack of asurveillance capability can be detrimental to securing the perimeter. Ifa security threat cannot be identified and responded to before it is toolate, then the effort for enforcing barriers and preventing unauthorizedaccess can be severely hampered. Using the wireless network camerasystems described herein, the perimeter can be visually monitoredwithout risk to military personnel.

With the vast expanses that a border patrol monitors, it is impossibleto visually monitor all activity using border patrol agents. Using thewireless network camera systems described herein, remote monitoring ofborder regions can be achieved. A larger number of vital regions of theborder can be monitored for unauthorized access using the same number ofborder agents, providing cost savings while improving efficiency. Byintegrating internal video analytics software, dynamic frame and bitrate control (e.g., allowing for slower frame and bit rates when nothingis happening, but switching to faster frame and bit rates for improvedvideo quality during critical events), and satellite IP access into thebase station, border regions can be covered.

Mining and Underground Applications

Underground mine safety has emerged as a pressing issue worldwide.Various countries and states have begun using communication technologiesto improve mine safety. One primary objective is to maintain andascertain the health and well-being of mining personnel during normaland emergency conditions. New technologies are applied to address voicecommunications, however, video surveillance and monitoring can provideadditional avenues to increase safety. Furthermore, video surveillancecan be used to gather information and improve the efficiency and reducedown time for mining production. However, the inherent nature of miningis not conducive to wired camera deployment. The wireless camera systemdescribed herein can be implemented to monitor underground and mining byvideo surveillance.

Difficult Environments

In many environments (e.g., near or under water or hazardous chemicalenvironments), access to wired power supplies can be difficult if notimpossible. One example can be the environment in and around swimmingpools. In such environment, wireless camera systems described herein canbe implemented to monitor pool safety by video surveillance.Additionally, in a chemical plant or processing plants where caustic orhazardous material conditions may not allow power cabling to exist orwhere the installation of power cabling may be impractical, the wirelesscamera system described herein can be implemented to monitor plantsafety by video surveillance.

Alarm Verification

Due to the number of false alarms created by security systems, manypolice departments are reluctant to respond to alarms unless there hasbeen “visual verification” that the situation merits a response. Thewireless network camera systems described herein can provides an easy toinstall (no power needed) camera system to allow for remote visual alarmverification.

FIG. 1A shows an example of a battery powered wireless camera 100 for awireless network camera system. One energy-saving feature of the batterypowered wireless camera 100 is that the web server has been removed fromthe camera 100 itself. By not having the web server functionality in thewireless camera 100, the camera 100 need not constantly be ready torespond to access from remote clients, which access the web server toinitiate data transmission. In one implementation, the wireless networkcamera 100 can be powered for many months using an internal battery 102.The battery 102 can include, e.g., solar cells, galvanic cells, flowcells, fuel cells, kinetic power generators, or other environmentalenergy sources.

Battery powered wireless network camera operation can be achieved, forexample, at full-motion frame rates in excess of 10 frames per second ata resolution of 320×240 pixels. The wireless camera 100 can be connectedthrough one or more wireless networks with a base station 135. Thewireless camera 100 can include multiple radios. For example, wirelesscamera 100 can include a high-bandwidth radio frequency (RF) transceiver104 and a low-bandwidth RF transceiver 106 for communicating with thebase station 135 via one or more wireless channels. The wireless camera100 can include a central processing unit (CPU) 110 for controllingvarious functionalities associated with the camera.

In certain implementations, the CPU 110 can be replaced by a simplifiedmicro-coded engine or state machine, or a hard-coded state machine. Forexample, the micro-coded engine or state machine can be similar to thatof an RF ID tag with limited response to input. This is because thewireless camera 100 can perform a limited number of predefined functionsand those functions can be programmed into the micro-coded engine orhard-coded state machine. In this manner, the power requirement and thecost of the camera can be reduced. In an alternative implementation,various components of the CPU 110 can be combined into a single ASIC,which integrates the entire active and some passive components andmemory in order to achieve power savings. Flash memory or other memorycomponents can be the only exceptions to this integration.

The CPU 110 includes a general purpose microcontroller 112 running alight real time operating system. Alternatively, in order to reduceoverhead the microcontroller 112 may not use an operation system. Themicrocontroller 112 can execute programs from an external memory such asa flash memory 114 external to the microcontroller 112 or from memoryinternal to the microcontroller 112. The CPU 110 also includes animage/video compression engine 116, which can perform proprietarycompression algorithms or a standard algorithms such as MPEG2, MPEG4,MJPEG, JPEG, and JPEG2000, and the like. Memory contained in the CPU 110(e.g., flash memory 114 or other memory devices) can store bothcompressed and uncompressed video.

In one implementation, the compression algorithm can generate data thatrelates to the relative visual importance of the compressed data bits.This data can be utilized by the forward error correction (FEC) sectionof the wireless radio (e.g. the high-bandwidth radio 104). The FECsection of the wireless radio can provide “un-equal protection” (UEP) tothe transmission of the compressed data as dictated by its importance.The complementary decoder can be implemented in the base station 135.This transmission scheme can achieve increased efficiency for thetransmission of the image data. One example of such transmission schemeis a publication by Yanjun Hu, et al. entitled “An Efficient JointDynamic Detection Technique for Wireless Transmission of JPEG2000Encoded Images.”

The CPU 110 also includes an audio compression engine 118. Memorycontained in the CPU 110 can store both compressed and uncompressedvideo, as well as compressed and uncompressed audio. Under low batteryor poor data radio channel bandwidth conditions, a relatively largeamount of energy can be saved by disabling the bulk high-bandwidth radio104 and not transferring the image, audio or other data to the basestation 135. In this mode, the flash memory 114 can be used to hold asignificant amount of data—up to many hours until the data is retrieved.

In conditions where the radio transmissions are interrupted or jammed;for example, by an intruder, an alarm can be initiated silently from thebase station 135 to the external network or can be externally indicatedby visual or audible transducers activated on the base station 135 orwireless camera 100. In one implementation, alarms can be triggered ifdata transmissions fail for a specified amount of time. This failure indata transmission can be caused by an intentional jamming by an intruderor by a failure to establish a transmission link. In such situation, thewireless camera 100 can store images and/or audio data in a storageelement, such as a flash memory 114, for transmission or retrieval at alater time.

Data retrieval at a later time can be achieved by manually removing thecamera 100 or storage element from the camera 100 and connecting to aWindows, Linux or Macintosh based computer via a Universal Serial Bus(USB). The storage unit can appear to the computer to be a standard massstorage device with files of the captured data. In anotherimplementation, when there is a failure in data transmission, the systemcan use an alternative wireless connection to transfer data, forexample, such as operating on a different frequency, using differentmodulation methods, or by increasing the output power of the wirelesstransmitter.

The compression engines 116 and 118 can operate on captured data outputfrom the sensors connected to the CPU 110. Alternatively, thecompression engines 116 and 118 can operate on captured data temporarilystored inside the flash memory 114. In this manner, the compression andcapture processes can operate on independent cycles. This independencecan also help maximize energy efficiency. For example, the image capturemay be occurring 5 times a second, but the compression engine mayoperate at very high speed on multiple images every 3 seconds. In thisfashion, the energy requirements of starting up the compression engines116 and 118 can be amortized over a large amount of data. In oneexample, the flash memory 114 can hold approximately 15 uncompressedimages before the compression engine is activated.

In some implementations, most or all components of the compressionengines 116 and 118 can be integrated into the microcontroller 112 andperipheral blocks. In this way, the compression can be achieved in themicrocontroller 112 using a hybrid software and hardware accelerationfor computational intensive processing. Other alternatives for thecompression engines 116 and 118 can include a separate applicationspecific integrated circuit (ASIC) or a field programmable gate array(FPGA). An example FPGA can be one based on flash technology such asActel Corporation's Fusion product line, where the “instant on” allowsfor rapid start-up capabilities reducing energy wastage during thecycling process. Alternatively, the image capturing module 120 can havean integrated compression engine and output compressed data directly tothe CPU 110.

The CPU 110 can also perform the burst transmission store/control MACprocess needed to transfer the data transmission from the bulkhigh-bandwidth radio 104. The high-bandwidth radio 104 can be powercycled based on the physical layer characteristics of the radio andsustained bandwidth needed to maintain certain fidelity of the imagesand audio transmitted. The power cycling of the high-bandwidth radio 104is further described in more detail below.

In general operation, the microcontroller 112 can be started from a deeppower save mode by the clock 111, which can be, e.g., an ultra low powerreal time clock. The timing of this can vary depending on the aggregateneeds of the multiple processes as they cycle. Therefore, once poweredup the software can be used to initiate or manage one or more processesincluding image capture, data transmission, and image compression. Insome instances, the clock 111 can be replaced by a microcontroller withintegrated low power real time clock capability. An example of such amicrocontroller is the Texas Instruments MSP430 family of products.

In one implementation, most or all of the timing required for thewireless camera 100 can originate from the base station 135 and becommunicated to the wireless camera 100 through a secondary receiver(e.g., the low-bandwidth radio 106), as will be described in more detailbelow. This configuration can act as an alternative to using the clock111 described above, and allow for more of the processing complexity toreside in the base station 135. Additionally, the wireless camera 100can be simplified, cheaper, and more robust. Furthermore, the wirelesscamera 100 can consume less power because very little timing processingwould be needed in the wireless camera 100. In this way, the wirelesscamera 100 can act as a “slave” unit and the commands for the processingelements described below can be issued directly from the base station135.

In general, all the processing can operate on cycles independent of eachother to maintain maximum efficiency. Memory can be used to buffer databetween processes to allow for this. This buffering memory can be usedto ensure that data overrun or data under-run does not occur duringoperation. This buffering memory can be designed to operate at anextremely low power during non active or retention modes that can occurbetween processing cycles. This buffering memory can be distributedbetween some or all of various integrated circuits that constitute thewireless camera 100. Alternatively, a portion of the buffering can beconcentrated in specialized memory components. An example of this kindof memory component can be the Cypress Semiconductor Corporation's 16Mbit SRAM memory product CY62167EV18.

As shown in FIG. 1A, a number of modules can interface to the CPU 110.The image capturing module 120 can include a low power imager such as aCMOS based sensor. Alternatively, a CCD can be used, but typically thesedevices use more energy than CMOS devices for a given frame rate,resolution and fidelity. The circuitry supporting the sensor can includememory to temporarily hold uncompressed images. In one implementation,image capturing module 120 can also include an image compression engineand memory that stores both compressed and uncompressed images. In someCMOS imagers, so called “active pixel” technology can be used to allowthe imager to power up and respond very rapidly to an image exposurecommand and then automatically power down.

In some implementations, the imager can have a number of active circuitsper pixel (such as analog to digital converters) to enable for rapidoperation for brief periods of time, followed by very low power standbyenergy consumption. This also means that the instantaneous powerconsumption of the imager can be relatively large during the framecapture and transfer process. In an alternative energy savingimplementation, the compression circuitry including the required memorycan be integrated directly onto the image capturing module 120 or evendirectly onto the image sensor die. This further integration can reducethe energy needed to transfer data and control information betweenintegrated circuits.

The sound detection module 122 can generate compressed or uncompressedaudio data. If uncompressed data is generated from module 122 then theCPU 110 can perform the compression. The sound detection module 122 canalso operate at low power, e.g., in the order of tens of micro watts andprovide a trigger output based on the noise level. The noise-leveltriggering event can be detection of a shock wave, detection of breakingor shattering glass detection or other similar acoustic detectiontechniques. In some implementations, the sound detection module 122 canoperate continuously and a positive noise trigger output can be used toactivate the wireless camera 100 from a standby mode. Once activated,the wireless camera 100 can initiate the various processing sections tostart cycling and, for example, start sending the surveillance data tothe base station 135.

In another noise-level triggering mode the sound detection module 122and the image capturing module 120 can continuously capture and store anon-going window of surveillance data of the immediately previousseconds, minutes or hours. During this time the bulk high-bandwidthradio 104 can be inactive in order to save power. However, once motionis detected some or all of the previously stored information can betransmitted to the base station or retrieved in other ways. This allowsthe activities that occurred in the area under surveillance prior to atrigger event to be investigated.

In a derivative behavior in this mode, different video compressionalgorithms operating at different rates can be used before and after thetriggering event. For example, JPEG, MJPEG or JPEG2000 type compressionalgorithms can be used during the pre-trigger period and MPEG2 or MPEG4type compression algorithms can be used during the post trigger period.This can avoid losing critical captured information on the activities inthe surveillance area in a time period leading up to the triggeringevent.

The infrared detection module 124 can operate at low power, in the orderof tens of micro watts, and provide a trigger output that indicatesmotion has been detected. For example, the infrared detection module 124can be implemented with a pyroelectric infrared sensor with a Fresnellens. In some implementations, the infrared detection module 124 canoperate continuously and a positive noise trigger output will activatethe wireless camera 100 from a standby mode. Once activated, thewireless camera 100 can initiate the various processing sections tostart cycling and, for example, start sending the surveillance data tothe base station 135.

The ultrasonic detection module 126 can operate at low power, in theorder of tens of micro watts, and provide a trigger output thatindicates motion has been detected. For example, the ultrasonicdetection module 126 can be implemented with a ultrasonic transmitterthat sets up a specific sound wave pattern that is received by anultrasonic receiver. Motion of objects in the field of the sound patterncan affect the received ultrasonic pattern by the receiver. Thesechanges can be detected by the ultrasonic receiver circuitry in theultrasonic receiver and this event can be used to activate the wirelesscamera 100 from a standby mode. Once activated, the wireless camera 100can initiate the various processing sections to start cycling and, forexample, start sending the surveillance data to the base station 135.

In another noise-level triggering mode the infrared detection module 124and/or the ultrasonic detection module 126 and the compression and/orcapture processing engine can continuously capture and store an on-goingwindow of surveillance data of the immediately previous seconds, minutesor hours. During this time the bulk high-bandwidth radio 104 can beinactive in order to save power. However, once motion is detected someor all of the previously stored information can be transmitted to thebase station or retrieved in other ways. This allows the activities thatoccurred in the area under surveillance prior to a trigger event to beinvestigated. In addition, other detection methods can be implemented ina manner similar to that described above for the infrared or ultrasonicdetection, but the triggering events can be initiated by other sensorsincluding magnetic sensors, relay or micro switches and window screenwired detectors.

The bulk high-bandwidth radio 104 can be a radio frequency and basebandchipset that implements the physical layer of the 802.11 standard. A keypurpose of this radio transceiver is to transfer the bulk of thecaptured and compressed surveillance data to the base station 135. TheMAC and other circuitry may or may not comply with 802.11 standards. Thechipset transceiver activities can be power cycled based on methodswhich will be discussed in further detail below.

Implementations of the techniques described here can be used to achieveefficient use of the high-bandwidth radio 104 in terms of energy per bitper unit of range (distance between transmitter and receiver)transferred. When active the radio can draw or dissipate relativelylarge amounts of power, however, due to the power cycling techniques,the power consumption of the wireless camera 100 can still besubstantially low. In particular, modulation techniques that use broadfrequency channels in the order of 5 MHz can be used. This is becausethese techniques exhibit low energy per bit (of data) per distance oftransmission. In one implementation, a multi-carrier modulationtechnique such as orthogonal frequency division modulation (OFDM) can beused. In another implementation, a spread spectrum modulation schemesuch as code division, multiple access (CDMA) can be used.

The low-bandwidth radio 106 can be, e.g., a low-overhead, long-rangeradio transceiver. The low-bandwidth radio 106 can be a radio frequencyand baseband chipset that implements any low power, low-bandwidthtechnique that will likely have longer reach and higher reliability thanthe bulk high-bandwidth radio 104. One purpose of the low-bandwidthradio 106 is to transfer status, control and alarm information to andfrom the base station 135. In receive mode, the power consumption can beextremely low in comparison to the bulk radio 104 and can be low enoughto allow the low-bandwidth radio 106 to operate continuously. Forexample, the power consumption can be in of the order of tens of microwatts.

Using this approach, the low-bandwidth radio 106 has a low power modewhere the radio 106 can be activated to respond to a short duration,beacon transmission that originates from the base station 135. The bitstream information contained in the beacon transmission can identify thecorrect camera and can also have other command/status information. Inanother implementation, the low-bandwidth radio 106 can be used as abackup when the bulk radio 104 fails or is disable, e.g., due to jammingsignals. In this manner, reliability of the wireless camera 100 can beincreased because there are a primary high-bandwidth radio 104 andsecondary low-bandwidth radio 106 for redundancy. In certainimplementations, the high-bandwidth radio 104 and the low-bandwidthradio 106 can be in the same transceiver block.

Additionally, errors in the bit stream of the beacon during transmissioncan be corrected by using forward error correction (FEC) techniques,such as hamming codes. Details of the forward error correction and itsassociated timing and phasing techniques will be described below. Thebit stream can serve as a “wake-up” function, allowing the base station135 to activate the correct wireless camera to wake-up and performcertain tasks during times when many components of the wireless cameramay be in the shut down mode. In one implementation, this low-bandwidthradio 106 can be achieved using “multi-standard” radio design, which mayshare portions or components used in the bulk radio 104. The sharing of“multi-standard” components can lead to lower cost or power from anoverall system perspective.

As noted above, the wireless camera 100 includes an internal battery102, which can be a standard non-rechargeable battery or a battery pack.In one implementation, a combination of rechargeable andnon-rechargeable batteries can be used. In another implementation, therechargeable battery can be replaced or augmented by so called supercapacitors. Such capacitors are readily available, e.g., from companieslike Maxwell Technologies Inc. The sources for the recharging energy caninclude, e.g., solar cells, fuel cells, galvanic cells, flow cells,kinetic power generators, and environmental energy sources. These energysources will be describe in more detail below.

The wireless camera 100 can make use of extensive active, highefficiency, power regulation and boaster circuitry to optimize the useof the energy available from various sources. Some or all of electronicprocessing and memory elements can be integrated into a single ASIC toreduce cost and power, creating a single chip wireless camera. Inaddition to the components shown in FIG. 1A, a Pan, Tilt and Zoommechanism and control can also be included for user control of thewireless camera 100. Optionally, wireless camera 100 includes LED 108.

FIG. 1B shows an example of a base station with a digital portalinterface. A base station 135 can include a wireless camera interface142, and a video signal processing module 146, and a video bandwidthshaping module 148, and a digital portal interface 152. Video storage150 can include a hard disk drive or a memory such as flash. In someimplementations, video storage 150 can include additional storageprovided by a removable flash storage module. In some implementations, adigital portal interface 152 can include a network adapter such asEthernet or a wireless interface such as WiFi, WiMax, or cellularinterfaces and a processing unit configure to communicate with a digitalportal such as a web portal or video portal and to receive digitalinformation such as video, images, or audio from the video bandwidthshaping module 148. In some implementations, a base station 135 caninclude one or more processing units to perform the operations of avideo signal processing module 146, video bandwidth shaping module 148,and to communicate with a web portal or video portal device; and digitalportal interface 152 can include a wired or wireless network interfaceto communicate with the video or web portal. Some implementations caninclude an alternate camera source interface 144 to communicate withdifferent types of wireless cameras and/or wire-line cameras such ascameras with Ethernet or USB interfaces. A base station 135 can includea user interface 154 to provide an interface for base station 135 and/ora control interface to communicate with the video or web portal viadigital portal interface 152.

FIG. 1C shows an example of a video delivery system. A video deliverysystem can include one or more wireless cameras 100, a base station 135,and a video portal device 185. A wireless camera can transmit a videofeed to base station 135 and the base station 135 can process the videofeed before sending the feed to the video portal device 185. In someimplementations, a wireless camera 100 is arranged in a wearable formfactor so that the wireless camera can be worn on a person, and caninclude a battery.

In some implementations, a network 195 can connect the base station 135,video portal device 185, and one or more remote clients 190. Network 195can include multiple networks and/or different types of networks. Forexample, network 195 can include a wireless network and the Internet. Insome implementations, base station 135 can communicate with a videoportal device 185 via a wired or wireless network such as 3G/4Gcellular, wired Ethernet, a WiFi network, or a WiMAX network. In someimplementations, a video portal device 185 can include one or moreprocessing units to perform operations described herein. A video portaldevice 185 can host a web server to deliver digital information such asvideos, images, or audio to one or more remote clients 190 via a networksuch as the Internet. In some implementations, a video portal device 185can include a remote surveillance application to control one or morewireless cameras 100, and can include support for multiple browserclients such as desktop PC, cell phones, and smart phones browserclients.

A wireless camera 100 can transmit digital information, such as imagesor video, to a video portal device 185 via the base station 135. Remoteclients 190 such as a mobile device, cell phone, smart phone, computercan view or access the digital information by communicating with thevideo portal device 185. In some implementations, a remote client canrun a web browser to access a web server hosted on a video portal device185.

A digital portal interface 152 can receive instructions from a networkdevice such as a web portal or a video portal device 185. Examples ofinstructions include how to configure, compress, and select video cameraimages for transmission to a remote client 190. In some implementations,a remote client 190 or video portal device 185 can initiate and transmitone or more instructions. In some implementations, a camera 100 caninitiate and transmit one or more instructions to control a video feed.A video bandwidth shaping module 184 can receive instructions from adigital portal interface 152 or a user interface 154. Instructions maycome from a remote client 190 via a video portal device 185.

A video bandwidth shaping module 148 can produce a data feed to send orstream to a video portal device 185 based on characteristics, e.g.,source, how, when, time, of one or more video feeds received or streamedvia an interface such as a wireless camera interface 142 or an alternatecamera source interface 144. In some implementations, a video bandwidthshaping module 148 can compress a video feed. Video signal processingmodule 146 can perform one or more operations such as compression,object recognition, image stability processing such as anti-shake,motion detection, and fire detection. A base station 135 or a videoportal device 185 can originate notifications such as emails, textmessages or other alerts based on events such as detected motion orfire. In some implementations, video storage 150 can store high qualityvideo and base station 135 can transmit preview quality selections ofthe high quality video to a video portal device 185.

A base station 135 can support multiple wireless cameras, can supportone or video surveillance applications, e.g., Axis communications API,can capture images from a wireless camera's video or image feed based ona timer or when motion is detection at the camera, can emulate a USBwebcam interface, can include a LCD viewing device, and can include abattery. A base station 135 can connect to a selected wired IP cameravia an interface such as alternate camera source interface 144. A basestation 135 can connect to devices such as a cell phone via connectionsthrough a USB modem or network interface. A base station 135 can includea broadband wireless card for wireless communications with the videoportal device 185 and/or the Internet.

FIG. 1D shows a different example of a video delivery system. A wirelessdevice can provide communication between a video hub/base station andthe Internet. The video hub can receive video from wireless cameras forvideo that are wearable. In some implementations, a wearable wirelesscamera can weigh less than 100 grams. A video portal suite server canact as a delivery channel between the video hub and devices such as asmart phone, cell phone, laptop, personal video player/recorder (PVR),or a desktop.

FIG. 1E shows an example of a video base station and system. A basestationed configured for video can also be referred to as a video basestation or video hub. Such a base station can use an interface similarto wireless camera interface 142 to communicate with wireless cameras.

FIG. 2A shows an example of a battery powered wireless network camerasystem 200 for video surveillance applications. In this example, thewireless network camera system 200 includes a wireless camera 210, abase station 220, a wireless link 240 connecting the wireless camera 210and the base station 220, and a remote client 250. The system 200 canfurther include a network 260 connecting the base station 220 and theremote client 250. The network 260 can be a LAN or wide area network(WAN), a wireless network (e.g., WiFi, WiMax, or cellular networks), orpower over Ethernet network (e.g., based on the IEEE 802.a3f standard).In some implementations, this network connection can be replaced by auniversal serial bus (USB) interconnect directly connected to acomputing device. From the client 250 or network 260 perspective, thewireless network camera system 200 can support extensive protocolsincluding IP, HTTP, HTTPS, 802.1x, TCP, ICMP, UDP, SMTP, FTP, DHCP,UPnP™, Bonjour, ARP, DNS, DynDNS, and NTP. The base station code cancomply with well established IP camera API's from companies such as Axiscommunication's “VAPIX” API or similar API's.

A suitable wireless camera in FIG. 2A can be implemented in variousconfigurations, including the wireless camera 100 described in FIG. 1A.In one embodiment, wireless camera 210 includes image capturing module202, trigger detection modules 204, burst transmission module 206, rapidsetup teardown module 208, high-bandwidth radio 212, low-bandwidth radio214 and storage device 216. The base station 220 can receive information(e.g., video and audio information) from the wireless camera 210 throughthe wireless link 240 and process the received information. The basestation 220 can also be one or more computers performing similarfunctions as a wireless base station 220 and running a surveillanceapplication. Hence, the computers can function as the base station 220and the client 250. For example, FIG. 2B shows another battery poweredwireless network camera system 270 for remote surveillance applications,where the surveillance client runs on the same system as the basestation 220, and the virtual web server in the base station 220 can beeliminated. Wireless camera 210 optionally includes image capturingmodule 202, trigger detection modules 204, burst transmission module206, rapid setup teardown module 208, high-bandwidth radio 212,low-bandwidth radio 214 and storage device 216. Base station 220optionally includes burst reception control module 224, rapid setupteardown module 226, high-bandwidth radio 228, low-bandwidth radio 230,storage device 232 and surveillance applications 252.

Referring back to FIG. 2A, in one embodiment, base station 220optionally includes virtual web server 222, burst reception controlmodule 224, rapid setup teardown module 226, high-bandwidth radio 228,low-bandwidth radio 230 and storage device 232. The base station 220includes a virtual web server 222 for relaying processed information toa remote client. The web server 222 can act as a virtual/proxy webcamera server. Further, the web server 222 can shield the remote client250 (running a surveillance application) from the burst transmissionmechanism (which will be discussed in further detail below) of thewireless camera 210. In addition, the web server 222 can act as avirtual web server or relay server for a number of wireless cameras,aggregating the video streams but appearing to the surveillance remoteclient 250 as multiple separate virtual IP cameras. The web server 222can therefore relay the camera data to the surveillance client 250 usingstandard network means such as IP, HTTP, HTTPS, TCP, ICMP, UDP, SMTP,FTP, DHCP, UPnP™, Bonjour, ARP, DNS, DynDNS, 802.1X, and NTP.

As described above, by removing the web server for a network camerasystem out of the wireless camera 210, the wireless camera can achieveultra-low power consumption. However, unlike the wireless camera 210,the base station 220 requires a relatively robust external power supplyto allow for continuous operation of the web server 222. This powersupply can have a battery back-up to enable operation for periods ofhours to days during main power loss. It may also be possible to powerthe base station 220 from a large battery which is charged by arelatively large solar cell panel. In another implementation, the basestation 220 can obtain some or all of its power through a power overEthernet (POE) methods, such as the IEEE 802.3af standard. In this casealso the unit may have battery back-up capabilities.

Furthermore, the base station 220 can be a self-contained unit with nokeyboard or monitor to enable a small form factor. For example, the basestation 220 can have a form factor similar to that of a “wall wart,”which is a small power-supply brick with integral male plug, designed toplug directly into a wall outlet. Additionally, the wall-wart style basestation 220 can use the Power over Ethernet methods for communicationswith the client device. In this manner, the base station 220 can be easyto install because it can be readily plugged in to a power socket. Thebase station 220 can also use flash memory or rotation media to storecaptured data.

As noted above, audio/video data can be requested by the clientapplication system through the network 260 and serviced by a virtual webserver 222 in the base station 220. Typically, the remote client 250consists of computer running a software application that analyzes and/orstores data for security and surveillance purposes. Multiple cameras canbe connected to a base station 220 via the wireless link 240. The clientcomputer can in turn run a surveillance application to access theconnected cameras. The client application can query the virtual webserver 222 in the base station 220 using standard or de-facto APIs suchas those available from Axis communications. The base station code cancomply with well established IP camera API's from companies such as Axiscommunication's “VAPIX” API or similar APIs. Remote client 250optionally includes surveillance application 252 and storage device 254.

In one implementation, the base station 220 can be connected to theInternet through a cable modem or a DSL modem. In this manner, the IPaddress of the cable modem or DSL modem can be dynamically assigned. Theconstant changing of the IP address can make it more complicated tobuild a virtual web server on the base station 220 and provideaccessibility to clients on the Internet. A dynamic domain name server(DDNS) service can be used to allow users anywhere on the Internet to“find” the base station web server 222, even if its IP address isconstantly changing. A DDNS function can be provided to enable a fixedname for the web server so that remote users on the Internet can findthe IP address of the web server.

In certain implementations, the base station 220 can include softwarethat determines the dynamically changing IP address and forwards a newIP address to the DDNS. This can occur every time a new IP address isassigned by the local Internet Service Provider (ISP). The software cansend the necessary updates to all of the DDNS host names that need it.The user or remote client software can use a specifically constructed“domain name” and this would be setup in the DDNS hosting site.Therefore, if the IP address is changed by the local ISP then the DDNSupdates the DNS records and sets the TTL (time to live) to a value thatwill cause a propagation of the updated DNS record throughout theInternet. There are many common providers that provide hosting services,such as dyndns.org. Alternatively, domain names can be purchased or freeones can be obtained, but many of the free ones can have usagerestrictions.

Additionally, the remote client 250 can run on a handheld or wirelessdevice, such as a mobile phone, a personal digital assistance (PDA), asmartphone, or the like. In one implementation, the base station 220 caninclude image optimization processing software or hardware for relayingthe captured images to the remote client via a wireless applicationprotocol (WAP). For example, the base station 220 can perform imageformatting, coding and communication in order to optimize the imagequality and behavior to the characteristics of the network link and theconstrained nature (bandwidth/size) of the handheld device that isrunning the client viewing software.

This image optimization processing can enable the base station 220 toonly send portions of the image at a time or only send zoomed-in imageinformation (to best fit to the smaller screen and lower networkbandwidth of the handheld device), or send images with lower resolutionor at lower frame rates. For example, this feature can allow an end userto remotely view the output of the wireless cameras from the convenienceof a handheld device, such as a mobile phone. Remote viewing of thewireless camera output from a handheld mobile device can be offered asan additional service to the user from the mobile network carriercompany (e.g., AT&T). This can create an attractive revenue generationopportunity for the mobile network carriers.

The base station 220 can also include a low-bandwidth, low-power radiobeacon 230 for communication with the wireless camera 210 via a secondwireless link. The secondary radio 230 can be low power, however, thetiming of this secondary radio 230 needs to be accurate in order to usethe bulk, high-bandwidth radio transmission efficiently. Thepredictability of the secondary radio coming on and transmittinginformation may need to be in the order of less than one millisecondresponse time in order to avoid wasting the channel time of thehigh-bandwidth bulk radio.

The wireless link 240 can include one or more wireless links. Forexample, a first wireless link can be a high-bandwidth wireless link anda second wireless link can be a low-bandwidth wireless link. Inaddition, the wireless link 240 can be an RF connection, a lowcomplexity LF, UHF or VHF connection with a baud rate of a few to tensof kilobits, a Bluetooth connection, a cellular network, a wirelessEthernet network, a WiFi network, or a WiMAX network. Anotherimplementation for this type of radio can be seen in, e.g., “Low-power,super regenerative receiver targets 433-MHz ISM band”, as described inpage 78 of the February-2006 issue of Electronic Design News. Thenetwork 260 connecting the base station 220 with the remote client 250can be a wireless network (e.g., a Bluetooth connection, a cellularnetwork, a wireless Ethernet network, a WiFi network, or a WiMAXnetwork) or a wired network (e.g., LAN/WAN network, or POE network).

Several power saving techniques can be used individually or incombination to reduce the overall battery energy consumption in thewireless camera. These techniques are listed and explained in furtherdetail below:

-   -   1. Move the camera web server to the base station and re-deploy        it as a virtual web server.    -   2. Cycle the image/sensor bulk, high-bandwidth data transmission        radio based on the needs of the data rate and channel capacity.    -   3. Cycle the image capture module (hardware or software) based        on the most efficient use of the module vs. latency,        start-up/shut down time and storage capacity needs.    -   4. Cycle the compression module (hardware or software) based on        the most efficient use of the module vs. latency, start-up/shut        down time and storage capacity needs.    -   5. Use of a secondary low-bandwidth radio with a longer range        than the bulk radio for camera control and status report and        triggering signals.    -   6. Activation of the camera functions based on various        triggering events.    -   7. Use of environmental energy sources.    -   8. Use of pulsed high efficiency light emitting diode (LED)        devices to illuminate the field of view

Energy Saving Technique 1: Move the camera web server to the basestation and re-deploy it as a virtual web server.

One fundamental feature of the wireless camera describe in thisspecification is that the wireless camera does not directly servicerequests for data received via a web server or a relay server mechanism.This is because there is no need for a web server to be running in thewireless camera. Instead, data transmission can be initiated andcontrolled by the burst transmission store/control block of the wirelesscamera. A substantial power saving can be achieved through thistechnique because it eliminates the need for web server functionality tobe present in the camera and allows the link radio to power down untilsensor and image data has to be transferred, not when the clientapplication needs data. (See power saving technique 2 below for furtherdiscussion.). However, through the use of the web server mechanism thecamera data can be available to client applications using standardnetwork means such as IP, HTTP, HTTPS, TCP, ICMP, UDP, SMTP, FTP, DHCP,UPnP™, Bonjour, ARP, DNS, DynDNS, 802.1X, and NTP

Energy Saving Technique 2: Cycle the image/sensor data transmissionradio based on the needs of the data rate and channel capacity.

Technique 2 cycles a high-bandwidth radio bursting data on a periodicbasis determined by a burst period. Between the burst transmissions thehigh-bandwidth radio can be powered down. On average, the energy neededto transfer data can be optimized. In one implementation, an 802.11based physical layer technology can be used to transfer the bulk data.The physical layer technology used can include broadband high efficiencyOrthogonal Frequency Division modulation (OFDM) architectures. The OFDMmodulation technique can exhibit low energy per bit transferred per unitof range when compared to other commonly used radio link architectures,such as 802.15.4 OOC/FSK modulation techniques. For example, in an OFDMarchitecture using QAN 16, energy per bit of less than 6 nJ can beachieved at 50 meters indoors at 2.4 GHz (including forward errorcorrection processing needed) using the Okumura-Hata path loss model. Incontrast, a similarly configured narrow band radio may achieve around200 nJ per bit.

FIG. 3 shows an example of transmission circuitry in a wireless camera'sradio that includes multiple output circuits. The efficiency of awireless camera's radio can be enhanced by using multiple outputcircuits 305, 310, 315 that each include a power amplifier (PA) andantenna matching circuitry. The radio can arrange circuits 305, 310, 315in an array configuration. In some implementations, output circuits 305,310, 315 are biased differently to optimize their performance fordifferent output power level ranges. For each of the three outputcircuits 305, 310, 315, respective power amplifier and matching circuitare implemented, biased and configured to provide optimal output powerwhere efficiency is at or near its peak. For example, matching circuitryfor a power amplifier can be selected based on a power amplifier's biaslevel, and as a result, differently biased power amplifiers can couplewith different matching circuits for optimal performance. A selectorswitch for selecting output circuits can be placed before the outputcircuits 305, 310, 315 to minimize power consumption.

Transmission circuitry can select one of the output circuits 305, 310,315 based on wireless link conditions. Such selection can provide adesired or minimum transmit output power at the optimal PA and matchingcircuit efficiencies. In some implementations, a high bandwidth wirelesscamera transmitter can operate at 802.11g standard OFDM modulation ratesincluding 24, 36, 48 and 54 Mps. The wireless camera radio transmittercan operate using the 802.11n modulation scheme which can achieve 65Mbps using 52 sub-carriers and a forward error correction coding rate of⅚. In some implementations, a wireless camera's radio can include aburst transmission unit, and the burst transmission unit includesmultiple output circuits such as output circuits 305, 310, and 315.

The wireless camera media access control (MAC) for the high-bandwidthradio can be programmed to set-up/tear down connections as determined bythe Transmission Store/Control Block. This allows the high-bandwidthbulk data transmission radio to power down completely for extendedperiods of time.

When the radio is switched on it can be instantly assumed to belogically linked with the base station. In some implementations, aprimitive MAC layer can be used. Thus, the radio can avoid the usualdiscovery period, and advance to the authentication request and reply,followed by the associated request and reply messages in a three-wayhandshaking process. This differs from the regular beacon behavior of802.11 when operating in a rendezvous mode. Discovery sequences can besuppressed except during initialization/installation conditions. A verylight OS can run on the wireless camera to bring up the MAC with theminimal configuration. This can reduce the need for the power and timeconsuming mechanisms associated with current wireless link technologies.In certain implementations, the MAC layer can almost be entirelyeliminated from the camera and a rudimentary slave response can beimplemented which responds to control signals received from a secondary,low-power, low-bandwidth radio channel.

The algorithm for the burst transmission processing is a timing loopwhere data is transmitted based on the data rate used and the availablechannel characteristics. A calculation is done to determine the optimumtiming for the burst transmission and the system is then set up to matchthis as closely as possible. During non-transmission periods thehigh-bandwidth radio can be completely powered down. This can bedifferent from “doze” or “standby” modes often provided by commercialintegrated circuits. These modes often dissipate energy at levels thatcan defeat the possibility of extremely long term battery life. Duringthis non transmission time the high-bandwidth radio can use less thantens of micro watts of power.

The timing to transmit for the burst transmission is based on thefollowing parameters: Average Maximum Channel Bandwidth is representedby Bm in M bits per second (Mbps). Channel bandwidth is the averagebandwidth that can be achieved by the high-bandwidth link. Averagesustained Data Rate is represented by Bs in Mbps, which is the data rateof captured audio/video data. The higher the rate, the better thefidelity and frame rate of the transmitted information.

FIG. 4 is a diagram showing the burst data transmission, according tosome implementations. To take advantage of the fact that the sustaineddata rate Bs is much smaller than the capability of the bulk radio; thetransmission will be on for a brief period of time to burst the data.This period can be designated by Tx (sec), and the time period betweenbursts can be represented by Tc (sec), e.g.,

${Tc} = {\frac{{Tx}*{Bm}}{Bs}.}$Referring to the bottom of FIG. 4 , there can be a time associated withsetting up the link and tearing down the link. For example, the time toset up link is represented by Tsu (sec), and the time to tear down linkis represented by Ttd (sec). Therefore the aggregate time to set-up andtear down link Tw=Tsu+Ttd (sec). To obtain maximum power savingefficiency on the bulk, high-bandwidth radio, ideally the ratio of thetransmit time Tx to power down time should be equal to the ratio betweenBs and Bm.

During the Tx period, the power drawn by the high-bandwidth radio can bevery high relative to the power down periods. For example, the wirelesscamera that uses a 802.11n transmitter with diversity or multipletransmitter sections (including the more complex and power intensiveprocessing required for OFDM) can use between 100 mW to 1.5 W during theTx period instead of a few hundred microwatts in other periods. Thislevel of power consumption during the transmission of data can be adistinguishing feature of this system compared to existing “low power”remote sensor systems which use narrow band radio transmission andsimpler modulation schemes. Existing low power remote sensor systems mayrequire less power to operate when actively transmitting, but may havethe disadvantage of lower transmission bandwidth and data throughput.

Also, in image transmission operation, current battery operated camerasystems which transmit data intermittently have a transmitter-off totransmitter-on ratio of 10 or less. That is to say, the transmitter inthe existing wireless systems is on most of the time. In contrast,because of the high-bandwidth radio used for transmission, thehigh-bandwidth transmitter is on for a short period of time. In thismanner, the burst transmission of the current system has atransmitter-off to transmitter-on ratio of much greater than 10.

However, the system timing needs to take into account the “wasted” timenecessary to setup and tear down the link during which the radio isactive, which is Tw. In order to approach the ideal efficiency, periodTw needs to be amortized across a relatively long period of active datatransmission time (Tx). This means that the time in-between bursting theradio, as represented by Tc, can be extended as Tw increases to maintainthe same efficiency level. Hence the efficiency (E, in percentage) canbe given by

${{E = \frac{Tx}{\left( {{Tx} + {Tw}} \right)}} \cdot 100}\%$

Given the above, the average optimum time between transmission of theburst of audio/video (Tc) data for a given efficiency E, can bedetermined as follows:

${Tc} = {\frac{Bm}{Bs} \cdot {Tw} \cdot \frac{E}{E\left( {1 - E} \right)}}$Example parameters for this equation include setting Tw=3 ms (Optimizedsystem), Bm=54 M bits/sec (ideal 802.11g data rate), Bs=192 k bits/sec(5 frames/sec with 0.5 bits/pixel at 320×240, no audio), and E=75%.Using the example parameters, Tc=2.53 seconds. By manipulating the MAClayer as described herein, it is possible to reduce Tw to be less than 5milliseconds for a system co-existing with a normal 802.11 environment.

System latency (or lag) can be greater than or equal to Tc. If latencyis too high an unacceptable lag can occur between the capturing ofaudio/video information to its availability to serve a surveillanceapplication. To reduce latency without negatively impacting energyconsumption, significant optimizations need be made to the MAC behaviorin order to reduce Tw. In order to reduce time period Tw during steadystate conditions (i.e. not during discovery or initialization states)certain modifications can be made. For example, a modification to theregular beacon behavior of 802.11 can be made. When the high-bandwidthradio is switched on for transmission, it can be assumed to besynchronized with the base station. Thus, the usual discovery period canbe avoided and the high-bandwidth radio can advance immediately to theauthentication request and reply, followed by the associated request andreply messages. Further, when the high-bandwidth radio is switched on,communication can be made for data transfer only.

The above scheme can be a significant improvement because the wirelesscamera communication can operate on a time frame determined by the needto transmit data of interest, and not on a time frame determined by theclient surveillance software application. Also, when multiple camerasare connected to the network using this method, the transmission burstcycle for each camera can be set so as not to interfere which eachother. For example, this can be done at initialization time by the burstreception store/control processing module of the base station.

In one implementation, a timestamp can be inserted in the capturedimages based on the time that the images were captured by the wirelessvideo camera. In this manner, any latency between the time of datacapture and the time of viewing or manipulating the images at the clientdevice can be accommodated. For example, suppose that a series of imageswere captured at 12:00 a.m., however, due to a temporary failure ordelay in the transmission the client device does not receive the imagesuntil 12:10 a.m. The inserted timestamps in the captured images can beused as the reference point for image processing or manipulation. Theinsertion of the timestamps can occur at the camera or at the basestation.

The base station's high-bandwidth radio MAC firmware can take advantageof “knowing” for long extended periods of time what specific wirelesscamera radios are associated with it. This can allow set-up and teardown of connections without discovery sequences, by only requiringconnection via authentication request and reply followed by theassociated request and reply messages. The base station can beimplemented in various configurations. In one implementation, a basestation implementing standard 802.11 protocols can be used by thesystem.

Non-Clear Channel Environments

In a non-clear channel environment (e.g., during interference from othertransmitters which may be using the channel) the high-bandwidth radiotransmission period can be “skipped” and the data that was to betransmitted can be temporarily stored and transmitted on the nextavailable cycle. In these conditions, the period and timing oftransmission bursts can vary based on channel conditions.

For example, in one implementation, the camera can include a separatelow power circuitry to determine if a high-bandwidth radio transmissionchannel is open or not prior to a transmission cycle. This informationcan be used to determine if the high-bandwidth radio in the camera isactivated from a power down mode or that transmission period is“skipped” by the camera. Using standard 802.11 MAC protocol, if thechannel is open the camera can initiate the transmission process bysending a Request to Send (RTS) frame. The base station can then replywith a Clear To Send (CTS) frame. As specified by the standard, anyother node receiving the CTS frame should refrain from sending data fora given time.

FIG. 5A shows a flow chart of a MAC algorithm 500A that can be used bythe wireless camera. At 505, the wireless camera is initialized, e.g.,by going through a discovery mode. At 510, the wireless camera scans forthe base station. At 515, the system configures the wireless camera tosynchronize with the base station. Once the wireless camera has beeninitialized and synchronized with a base station, the camera can thenenter a power down or standby mode, at 520, when the camera is inactive.On the other hand, based on a triggering event as described above, at530, the camera can be powered on and enter active mode.

Once the camera is powered on, at 535, the camera transmits an RTS frameto the base station. If a channel is available, the base station canthen reply with a CTS frame. At 540, the system determines whether a CTSframe is received from the base station. If the CTS frame is received,at 565, the camera starts to transmit captured or stored image data. Onthe other hand, if the CTS is not received from the base station, at560, the camera stores the captured data in the storage device, andperiodically transmits an RTS frame to the base station.

In addition, once the RTS frame has been received by the base station,the base station scans for available channels, at 545. At 550, the basestation determines whether there are available channels to establishconnection with the wireless camera. If there is an available channel,at 555, the base station reserves the channel and then sends a CTS frameto the camera. On the other hand, if there is no available channel, thebase station keeps scanning for available channels.

In another implementation, the base station can include processingcircuitries or operating modes that can determine if a high-bandwidthradio transmission channel is open or not on a regular basis. Thischannel availability information can be transferred to the camera usingthe secondary low-bandwidth radio connection. One benefit of providingthis processing on the base station can be a significant power reductionin the camera, since the processing does not occur using the camera'spower. Also, the incorporation of the channel availability processingcircuitry or operating mode in the base station can allow for complexand power-intensive processing to be executed for system operation.

The base station can then emulate a standard 802.11 CTS/RTS handshakingoperation. In this manner, both the primary and the secondary radios ofthe base station can be used to establish handshaking. Here the basestation itself generates the RTS signal which would normally be expectedfrom the camera. This RTS signal can cause surrounding nodes to stay offthe channel. This can also eliminate the need for the camera to generatethe RTS signal and allow the camera to shut down between time periods ofactual data transmission. As noted above, the camera can be activated bythe secondary radio operation to transmit more data, or from an internaltimer. The whole sequence of emulated CTS/RTS handshakes of datatransmission can be pre-determined.

In one further implementation, if a high-bandwidth radio transmissionchannel is open, the base station can reserve and hold the channel. Itcan do this by using standard 802.11 MAC channel accessing techniques.Here the base station can start transmitting “fake” or “filler” energyinto the channel “as if” the packets were originating from the camera.During this sequence, the base station can signal the camera using thesecond wireless link that the bulk channel is open. The base station canthen immediately stop transmitting and can “release” the channel. Thetiming can be configured so that the high-bandwidth radio in the cameracan then be activated from a power down and transmission begins suchthat, from an external observing radio, the channel was never releasedfor any material length of time.

Additionally, the above method of “reserving” and “holding” of thechannel for a period of time can be implemented in the base stationusing the “CTS-to-self” signaling method in the 802.11 standard in aslightly modified way. This way, an association between the base stationand the camera can be established prior to the base station entering theCTS/self mode. FIG. 5B is a flow chart showing a process 500B that canbe used to implement the CTS-to-Self algorithm. Initially, at 570, thebase station scans for available bulk, high-bandwidth radio channels. At572, the base station determines whether the bulk, high-bandwidth radiochannel is available. If the bulk radio channel is available, at 574,the base station sends a CTS/Self signal to reserve the availablechannel for a wireless camera. If the bulk radio channel is notavailable, process 500B iterates at 570 and the base station continuesto scan for available channels.

In this manner, the CTS/Self signaling technique available in the 802.11standard can be used to keep the 802.11 nodes surrounding the basestation quiet for a period of time, thereby reserving the availablechannel. In some 802.11 exchange implementations, the CTS/self mayoriginate from the camera. In contrast, the base station process shownin FIG. 5B can generate the CTS/self signaling as a proxy to the remotenode, e.g., wireless camera.

Once the channel has been successful reserved by the base station, at576, the base station can then send rapidly, with low latency, aproprietary “wake-up/CTS” signal (somewhat similar to the CTS signal) tothe wireless camera via the secondary or low-power radio channel. Thisdiffers from existing 802.11 MAC procedures where the CTS information issent once through the primary (or bulk) radio on the camera. At 578, thecamera receives the CTS signal from the base station using the secondary(low-power) radio on the camera. The secondary radio on the camera, at580, then rapidly trigger a “wake-up” signal to the primary bulktransmission radio in the knowledge that the bulk (primary) transmissionchannel has been reserved and should be clear. At 582, the cameratransmits the image data to the base station via bulk transmissionchannel reserved by the base station. At 584, this image data isreceived by the base station via the high-bandwidth channel.

One potential advantage of using the above CTS-to-self signalingtechnique is that the bulk transmission (primary) channel can be heldopen according to 802.11 standards for a relatively long period of time.This period can be relatively long to allow for backward compatibilitywith much older (slower) bandwidth modulation schemes such as 1Mbit/sec. In the standard, the time reserved by a CTS-to-self can bedetermined by the duration field in the CTS frame. In this method, theCTS is sent by the base station with usual contention period rules (i.e.after the DIFS quiet air time), and it can be honored by any deviceclose enough to correctly demodulate it.

Methods and systems where a base station reserves a high bandwidthchannel and alerts a wireless camera when the channel is known to beclear and signaling this through a low-power secondary radio may offerseveral advantages. For example, such methods and systems cansignificantly lower the overall power requirement in a wireless camera,because the camera would not have to power up a power intensive bulktransmission receiver radio to determine if the channel is clear.Instead, the camera can power up a high-bandwidth transmitter when thechannel is likely to be clear of other WiFi compatible nodes in thenetwork.

Furthermore, the receive environment (or channel availability) for videoor audio data transmissions may be best determined at the receiving end,such as at a base station. This is in contrast to an 802.11 based methodwhere a camera performs Carrier Sensing (as part of the usual CarrierSense Multiple Access/Collision Avoidance (CSMA/CA) protocol). Themethods and systems presented herein may ensure that the high bandwidthchannel is at a point in a network where interference and collisions mayhave the most impact such as in terms of the energy seen at thereceiver. Therefore, a system where the base station takes advantage ofthis “local” knowledge may avoid hidden node problems that can occurwhen the wireless cameras are at great distances from the base station.Such a system may span extremely long distances, such as a mile, whilereducing the possibility of data collisions. As a result, such a systemmay lower the overall energy needed at a wireless camera forre-transmission of lost packets.

In addition, the secondary (low-power and low-bandwidth) radio canimplement a hierarchy of up-power modes to provide sustained ultra lowpower operation. For example, a “carrier sense” mode can be availablewhere only the front-end section of the radio is powered-up to detect ifa carrier of a certain narrowband frequency is present. This carriersense mode can be designed to be extremely low power and can beoperational for extended periods of time. In this method of operation,if the front-end section of the secondary radio detects a likely carriersignal, then further demodulation can be triggered to search for aspecific leading signature bit sequence. This sequence can be used todetermine if the signal is a valid transmission from the base station.If the sequence is valid, then further bits are decoded, if not then thesecondary radio can revert back to the low power carrier sense mode.

The method described above, i.e., that of using a low-power secondaryradio to receive control, “wake-up” and other information about thestatus of a primary high-bandwidth transmission channel is differentfrom existing wireless schemes. For example, one difference can includeusing one modulation scheme for the transmission of control informationand a different modulation scheme for the transmission of data (e.g.,captured image data) information. This can allow the receiver to below-bandwidth and be design to consume very low power. Anotherdifference from existing wireless schemes can be that the demodulationand/or carrier detection of the secondary radio can be on for extendedperiods of time in order to listen for the secondary channel and/ordemodulate the control/status information.

Furthermore, potential benefits can be achieved by having the secondaryradio on at all times when compared to a secondary radio that usespolling (i.e. comes on at intervals to poll for a transmission). Forexample, this can reduce the need to have timing synchronization with abase station, and can make the system design simpler and more robust. Inaddition, this can reduce primary channel (high-bandwidth channel)airtime consumption. The is because a polled secondary radio can, onaverage, add half the polling interval time to the time needed by thecamera to transmit the video images on the primary channel. Thisadditional airtime consumption can impact the overall efficiency of theprimary channel. This can affect other nodes sharing the channel in asignificant way by reducing their overall throughput. With carefuldesign techniques, this constantly on secondary radio can consume poweron average in the order of under 1 mW in power during extendedoperation. This can further allow the secondary radio to be availablefor many months to years using the energy from a small battery or afraction of the energy from a larger battery pack.

In some implementations, a base station can operate circuitry such as atransceiver to detect an availability of a wireless channel using acarrier sense multiple access/collision avoidance (CSMA/CA) protocol,e.g., IEEE 802.11 or WiMax standards base. In a wireless environmentwith one or more wireless cameras and one or more additional nodes, thebase station can transmit data to prevent the surrounding nodes fromtransmitting. For example, after detecting the availability, the basestation can transmit a wireless signal to one or more of the surroundingnodes within wireless range of the base station to cause the surroundingnodes to remain silent on the wireless channel. The base station cantransmit a signaling message signaling the availability of the wirelesschannel to a wireless camera node to cause the node to respond with awireless video data message. A wireless video data message can includeat least a portion of a video feed. The base station can receive andprocess video from the wireless camera node for remote viewing. In someimplementations, a size of the wireless video data message is greaterthan a size of the signaling message by at least a ratio of 100 to 1. Insome implementations, a wireless camera node can operate circuitry suchas a transceiver or receiver capable of receiving the signaling messagefor one or more periods of time averaging less than 5% of elapsed timeduring extended periods of video transmission. A wireless camera nodecan spread out these periods of time for receiving signaling messagesover a longer period of time. In some implementations, a base stationand a wireless camera node can have prearranged periods for transmittingand receiving messages. In some implementations, the wireless cameranode can use a 2.4 GHz radio spectrum to transmit the wireless videodata message.

Legacy Compatibility Advantages

A further benefit of methods implementing 802.11 MAC compliant protocolprocessing that include using a secondary radio is that the arrangementis a “good citizen” in a WiFi compatible environment and will behavewell with legacy standard 802.11a/b/g nodes. This can allow thedeployment to be widespread by not affecting normal operation of alegacy compatible network. In the above methods the latency to “wake-up”the camera through the secondary radio and set-up the link after thistrigger can be designed to be as low as possible and is the sameparameter as described above as Tsu. The accuracy of the secondary radioto wake up external circuitry may need to be predictable and shouldideally in the order of microseconds to avoid wasting bandwidth on theprimary (bulk) channel.

The methods and systems presented herein may have several channel andspacial efficiency advantages. Such methods and systems can use hightransmit bandwidth speeds exceeding 22 MBits/sec (Mbps). As a result,video and/or audio transported at or over the 22 Mbps rate will occupyless time of the available channels. This allows for better co-existencewith other nodes, because this increase available channel airtime forthe other nodes. These methods and systems can minimize interferencewith existing 802.11 nodes and users, and may allow additional camerasand nodes to occupy a given physical zone when compared to cameras thatuser lower bandwidth (narrow band) modulation methods.

Newer 802.11e Systems with QoS Schemes

In some implementations, the transmission cycles can adhere tostandardized system wide quality of service (QoS) schemes, such as thatof the IEEE 802.11e standard. The base station can implement a PointCoordination Function (PCF) between these beacon frames. The PCF definestwo periods: the Contention Free Period (CFP) and the Contention Period(CP). In CP, the DCF is simply used. In CFP, the base station can send aContention Free-Poll (CF-Poll) to each camera via the primary (bulk) orsecondary radio, one at a time, to give the camera the permission tosend a packet.

In some implementations, the IEEE 802.11e standard using the HybridCoordination Function (HCF) can be used. Within the HCF, there are twomethods of channel access, similar to those defined in the legacy 802.11MAC: HCF Controlled Channel Access (HCCA) and Enhanced DistributedChannel Access (EDCA). Both EDCA and HCCA define Traffic Classes (TC).The captured data transmission can be assigned a high priority usingthis scheme. Using the EDCA method, the base station can assign aspecific Transmit Opportunity (TXOP) to a specific camera. A TXOP is abounded time interval during which a specific camera can send as long asit is within the duration of the pre-assigned TXOP value. Additionally,Wi-Fi Multimedia (WMM) certified nodes need to be enabled for EDCA andTXOP.

Alternatively, the system can also use the HCCA scheme to allow for CFPsbeing initiated at almost anytime during a CP. This kind of CFP iscalled a Controlled Access Phase (CAP) in 802.11e. A CAP is initiated bythe base station, whenever it wants to send a frame to a remote node, orreceive a frame from a node, in a contention free manner. In fact, theCFP is a CAP too. During a CAP, the base station, which can act as theHybrid Coordinator (HC), controls the access to the medium. During theCP, all stations function in EDCA. The other difference with the PCF isthat Traffic Class (TC) and Traffic Streams (TS) are defined. This meansthat the base station (implementing the HC function) is not limited toper-camera queuing and can provide a kind of per-session service.

Furthermore, the HC can coordinate these streams or sessions in anyfashion it chooses (e.g., not just round-robin). Moreover, the stationsgive information about the lengths of their queues for each TrafficClass (TC). The HC can use this information to give priority to onestation over another, or better adjust its scheduling mechanism based onthe captured data burst transmission needs as described above. Anotherdifference is that cameras are given a TXOP: they may send multiplepackets in a row, for a given time period selected by the HC. During theCP, the HC allows stations to send data by sending CF-Poll frames. Withthe HCCA, QoS can be configured with great precision. QoS-enabledcameras can have the ability to request specific transmission parametersand timing as determined by the burst transmission needs describedabove.

Energy Saving Technique 3: Cycle the image capture module (hardware orsoftware) based on the most efficient use of the module vs. latency,start-up/shut down time, frame rate and storage capacity needs.

For example, in a possible power saving method, after the exposureprocess, the pixel read out for the image captured from the sensor mayoccur at the maximum clock output rates allowed by the sensor. This ratemay be many times the sustained data rate. This allows the sensor andassociated circuitry to power down for significant periods between frameexposures. The image capture engine/processing sections of the cameracan also power up and down on a periodic basis independent of othersections of the camera. When operating in the capture mode, uncompressedimage can be loaded into an SRAM memory, which temporarily holds thedata until it can be processed by the other main sections of the camera.When operating in the power-down mode this section can retain the datain SRAM or some other memory in a low power standby mode.

This cycling can allow the image capturing module to operateindependently of other sections. Therefore, each section can cycle on aperiodic basis most efficiently to save energy with respect to latency,start-up/shut down time, and storage capacity needs. Further, thiscycling technique can offer power savings over that of a simple powerdown mode where the whole camera except for a “wake-up” section ispowered down.

Energy Saving Technique 4: Cycle the compression module (hardware orsoftware) based on the most efficient use of the module vs. latency,start-up/shut down time and storage capacity needs.

The image compression engine/processing sections of the camera can alsopower up and down on a periodic basis independent of other sections ofthe camera. When operating in the capture mode, compressed image isloaded into an SRAM memory, which temporarily holds the data until itcan be processed by the other main sections of the camera. Whenoperating in the power-down mode this section can retain the data inSRAM or other memory in a low power standby mode.

This cycling can allow the compression module to operate independentlyof other sections. Therefore each section can cycle on a periodic basismost efficiently to save energy with respect to latency, start-up/shutdown time and storage capacity needs. Further, this cycling techniquecan offer power savings over that of a simple power down mode where thewhole camera except for a “wake-up” section is powered down.

The image compression algorithm in the wireless camera does not need tobe the same as the compression algorithm used in the base station forsending image information to the client application. For example, anon-standard, proprietary compression algorithm, which can be cheaperand/or consume lower power, can be used on the camera. The compresseddata from the camera can be transcoded to a well-know standard (e.g., aJPEG standard) by the base station; and therefore, the proprietary imagecompression algorithm of the camera can be “transparent” to the clientapplications. Alternatively, the compressed data can be relayed directlyto the client without transcoding by the base station, if the client canprocess the compressed data from the camera.

Energy Saving Technique 5: Use of a low-bandwidth transceiver with alonger range than the high-bandwidth data transmission transceiver forcamera control and status report.

Low-bandwidth, low power transceivers can be expected to draw onlymicrowatts of power in receive mode. The modulation techniques andfrequency band of the low-bandwidth radio can be different from thehigh-bandwidth data transmission radio. As noted above, thehigh-bandwidth and the low-bandwidth radios can be integrated togetherinto a single transceiver block having dual radios. For example, somehigh volume, low cost commercial chipset radios can include low rateradio modulation schemes for legacy or backwards compatibility reasons.A wireless camera system can include a direct-sequence spread spectrum(DSSS) receiver (which is a modulation scheme for 802.11b). The DSSSreceiver can act as the secondary command channel. In someimplementations, a wireless camera can include a duty cycle mechanism tominimize power consumption of the DSSS receiver.

The function of the low-bandwidth radio can be for side bandcommunication without having to power up the high-bandwidth radio. Itcan allow the camera to be “listening” for instructions during deepsleep mode configurations without needing relatively large power drain.The specifications of the low-bandwidth radio can have longer range butmuch lower bandwidth than the high-bandwidth radio. Thus, undersituations where the high-bandwidth radio cannot establish a link withthe base station, the low-bandwidth radio can operate as a back-up radioand effectively communicate with the base station.

The low-bandwidth radio can further reduce its “listening” energyconsumption by operating in a polling mode. In the polling mode, theradio section of the low-bandwidth radio can cycle from active tostandby. During the active mode, the low-bandwidth radio listens forburst transmission from the base station, captures the data and thengoes back to stand-by.

FIG. 5C shows an example of communications between a base station and awireless camera. A base station can determine cycle timing information.Furthermore, the wireless camera can know the cycle timing information.In accordance with the information, a wireless camera's receiver cansynchronize with the base station to power up receiver circuitry toreceive information, such as beacons, messages, or commands, from thebase station. A base station can transmit beacons several times persecond to maintain or minimize latency between capturing of digitalinformation such as images, audio, or videos and a transmission of thedigital information to the base station. In FIG. 5C, a wireless cameraoperates a secondary radio in a polling mode to receive information froma base station, the base station transmits information such as beacons,messages, or commands to the wireless camera.

Furthermore, the low-bandwidth radio can be used to receivePan/Tilt/Zoom (PTZ) information and other commands. These other commandscan be triggering operations such as transmission, capture andcompression or shut down for long periods of time. The low-bandwidthradio can further be used to send status information to the basestations regarding the health of various components on the wirelesscamera (e.g., the high-bandwidth radio). Because the low-bandwidth radiocan have lower latency than the high-bandwidth radio, the low-bandwidthradio can be used for two way audio communications.

Energy Saving Technique 6: Activation of the camera functions based onvarious triggering events.

As described in detail above, the camera operation can be triggeredbased by external conditions such availability of light, motion sensing,passive infrared (PIR) detector, sound or time of day, week or month. Inone implementation, the triggering event can occur through theprocessing of the captured image data.

Energy Saving Technique 7: Use of environmental energy sources. Asdescribed in more detail above, various environmental energy sources,such as solar cells, fuel cells, kinetic power generators and otherenvironmental energy sources can be used to power the camera.

Since the average power consumption of the wireless camera can berelatively small, a solar cell or solar cell array can be used as apower source for the camera. This solar cell or solar cell array can beused to recharge a battery or a high capacity capacitor which can powerthe camera during night time or low light conditions. Further, since thesolar cell can be small, it can be attached to a side of the housing ofthe wireless camera. A suction cap (e.g., a vacuum, push-on sucker) canbe mounted on the solar panel side of the housing. This can allow thecamera to be quickly mounted on the inside surface of a window pane of abuilding or a vehicle, such that the solar cell faces the outside tocapture light energy, while the imager lenses conveniently faces insideor outside the vehicle or building to capture images.

Additionally, the entire wireless camera can be recharged on a chargingstation or can have interchangeable battery packs that can fit into acharging station. For example, the interchangeable battery packs can besimilar to the batteries used for cordless phones or mobile phones. Theinterchangeable battery pack can also use non-rechargeable batteries.Furthermore, the wireless camera can be adhered to a surface with amounting mechanism. This mounting mechanism can be separate from thewireless camera. This mounting will have means that allow the cameras toattached to the mounting quickly and easily while keeping camera's fieldof view constant. In another embodiment the camera may be mounted on awindow pane using suction-cups.

In one implementation where a solar cell is used to charge arechargeable battery during hours of light, there can be wear-out of therechargeable battery. Typically re-chargeable cells can have a limitednumber of charge, recharge cycles. For example, if the rechargeable cellis good for 365 cycles, the cell can only be usable for approximatelyone year of day/night recycles, thus limiting the camera life toapproximately one year. To avoid this problem, an array of cells can beused by the camera. By selecting from a limited set of cells inside thearray that will be used for a given number of cycles, thecharge/discharge cycle burden can be distributed over the array.

In one implementation, an array of 12 rechargeable battery cells can beused. The 12 cells can be grouped in groups of three battery cells. Onegroup of three cells can be selected for a 12 month operation of chargeand recharge cycles. After 12 months, the next group of three cells canbe used, and during the third year the next set of three cells can beused and so on. In this way, overall usable lifetime of the rechargeablebattery cell array can significantly exceed that of a single cell.Alternatively, the division of the charge/recharge cycle burden can beachieved by a specialized circuitry that alternates charging betweencells or cell groups and on a varying timing cycle other than the 12month cycle as described above.

During the transmission periods of the high-bandwidth radio, the energyconsumption can be significant. Drawing a high current from a smallbattery cell directly connected to the camera power input can causeaccelerated wear out of the battery. Therefore, a high efficiencycircuit can be used to avoid the wear out of the battery by limiting themaximum current draw from the battery.

FIG. 6 shows an example of current limiting circuitry. Current limitingcircuitry 600 can couple with a camera's power input. Some circuitry 600implementations can include a battery pack 602 or alternative energysources such as solar cells, galvanic cells, fuel cells, kinetic powergenerators, or other environmental sources. Current limiting circuitry600 can also help maintain efficient operation in implementations withalternative energy sources.

Current limiting circuitry 600 can include regulator circuitry tocontrol the maximum amount of current drawn from a battery 602 or analternative energy source. This regulated current draw is then used tocharge a holding capacitor sub-circuit 610. The sub-circuit 610 caninclude a capacitor, a super capacitor, or other high reliability chargeholding device capable of handling current surges better than thebattery or alternative source. Current limiting circuitry 600 caninclude a switched regulator 604 (e.g., a buck regulator) or otheractive type regulator to maximize efficiency in charging the holdingcapacitor sub-circuit 610. A current sensor feedback loop can beimplemented to monitor the current applied to the holding capacitorsub-circuit 610. For example, one monitoring circuitry can be achievedby amplifying the voltage through amplifier 606 across a low value senseresistor 608 connected in series with the supply current.

Additionally, a second regulator can be used as a voltage regulator tosupply a controlled voltage source to the camera power input. Thisvoltage regulator can be implemented as a switched regulator 612 (e.g.,a buck regulator), or other active regulator to maximize efficiency insupplying a voltage source to the camera input. In one implementation,the power regulation circuit can have the ability to adjust the level ofcurrent drawn from the energy source under programming control. Forexample, this can be achieved by adjusting the gain in a sense feedbackloop or the set-point in the feedback voltage. This capability can allowfor a variety of alternative energy sources (or modes of operation ofthose sources) to be used.

A wireless camera can include multiple switches/settings available to auser to increase the camera's ease of use. For example, the camera caninclude features for operation in darkness (on/off), operation based onsound detection, operation based on infrared detection, and operationbased on other triggers. The camera can further include an option forthe user to choose the duration of operation (time period the cameraneeds to operate, e.g., 3 months, 6 months, 1 year or other similardurations). Software can be used to calculate frame rate that need to beused so that the batteries can last for the indicated time.

During set-up mode the camera's wireless link can be powered upcontinuously (not cycling) for an extended period of time to enable, forexample camera focus and field of view set-up to be configured simplyand easily. In applications where system latency may cause the period Tcto become unacceptable, the signaling to the low-bandwidth radio can beused to trigger faster cycling and reduce Tc. However, this can reduceenergy efficiency. Also, to make the base station easier to install, itcan be powered through the Ethernet cable using power over Ethernet byimplementing the IEEE 802.3af standard or similar methods.

The characteristics of standard 802.11 wireless links can often lead tounreliable or inconsistent connectivity. This is usually due tointerference or other environmental factors. This can make set-up and/oroperation erratic. These issues can be addressed through the followingmethods:

a) The media access techniques used by the system need not be the sameas the MAC standards of 802.11. Therefore, in poor connection conditionsspecific and more restrictive channel access techniques can be used byignoring other radios and forcing and holding a connection. If thesecondary low-bandwidth radio is implemented in the camera, thesetechniques can be triggered and controlled through the secondary radiosince it can establish a link in conditions where the high-bandwidthradio cannot. For example, the base station can include circuitry thatdetermines if a channel is available for the primary radio (bulkhigh-bandwidth radio).

b) Since the base station has information about the transmissionbehavior and expected state of the camera, it can detect and correctlink problems by requesting retransmission of the data. This request canbe sent via the secondary low-bandwidth radio which can be more reliablethan the high-bandwidth channel. This retransmission can be hidden andtransparent to the client surveillance application through the virtualweb server in the base station.

c) A highly asymmetrical radio link can be implemented for thehigh-bandwidth radio where the antennae and processing in the basestation uses high gain techniques such as multi antenna (MIMO) and highsensitivity RF front-end processing to help reliably capture thetransmission data from the camera.

Energy Saving Technique 8: Use of pulsed high efficiency light emittingdiode (LED) devices to illuminate the field of view

In applications where there is little light, or light has been disruptedby a disaster or a failure condition (e.g., an electrical failure), thecamera may operate in the dark and the image sensor may not captureuseful data. In conventional camera systems, this situation is addressedby attaching an auxiliary light source near or on the camera. Lightsources operating continually to illuminate an observation area duringvideo surveillance can consume significant energy. In oneimplementation, the wireless camera system described in thisspecification can save energy by pulsing a high efficient infrared orvisible light LED, synchronized to the image capture frequency andphase. The operational duration of this scene illumination light pulsefrom the LED can be minimized by a careful calculation of thesensitivity and exposure time needed by the image sensor to successfullycapture images. In addition, scene illumination using the LED devicesneed be implemented only when necessary to capture an image, and overallenergy consumption of the camera can be reduced.

Camera Shutdown and Privacy Enhancements

In applications where users would like to shut down (or deactivate)certain cameras, various enhancements can be used. In oneimplementation, for example, all or some camera may need to be shut downin situations where recording is not needed or is preferred to bedeactivated. This can include situations where an authorized resident ispresent such as inside the residence or premises. Another example can bea camera installation in a locker room or changing room for use whenthese facilities are expected to be empty. This can be due to privacyreasons, or simply that the system operator would prefer certain camerasto be off.

In the deactivated (i.e., non-recording) mode, the secondary,low-bandwidth radio can still be on, giving the camera the ability to bereactivated when necessary. Furthermore, this ability to shut down thecamera except for the operation of the low power secondary radio, canalso allow for longer battery life. Therefore, each camera can beindividually deactivated based on control information received via theprimary or secondary radio link.

The camera activation or deactivation can also be manually set by anoperator, or be linked to an existing alarm system or to a pre-settiming cycle. Deactivation can be overridden under certain circumstanceseither automatically (such as an alarm trigger), or manually (locally orremotely). Activation periods of the wireless cameras can be manuallyoverridden. In addition, these periods of override can themselves betimed to last a specific period of time, for example minutes or hours.Furthermore, for ease of use and convenience reasons, the setting,initiating and overriding of the modes of activation/deactivation ofcameras can be operated from a hand-held remote control.

A visual indication can be made available on the camera usingintermittent flashing LED. For example, a red LED can be used toindicate that the camera is in active recording operation. However, someobservers or personnel in the camera's field of view may not believethat the camera image recording or viewing capability is truly “off”. Inone implementation, to address this concern, the camera can have amechanically operated, privacy lens cap or an easy-to-observe, visibleshutter that obscures the camera lens in an obvious way to make it clearto the observer that the camera cannot be recording or capturing images.

For example, the material of the privacy lens cap can be an opaquematerial such as a solid sliding window that covers the entire front ofthe lens surface. To make the fact that the lens is obscured very clearto any observer, the privacy lens cap or visible shutter should bevisually clear. For example, if the casing of the camera is white, andsince the lens of the camera appears black, the privacy lens cap can bean opaque material such as a solid white sliding window. This way, anobserver will not see the darkness of the lens iris or any dark holes onthe camera that might indicate an image capturing capability.

A further mechanism to obscure the lens and achieve privacy enhancementcan be implemented by causing the lens to retract or roll back into thecamera case in such a manner that the lens is no longer pointing intothe observation area. For example, in a Pan/Tilt/Zoom (PTZ) type camerathis can be implemented by altering the design of the camera to extendthe rotational range of the PTZ mechanism beyond the usually implementedrange. Therefore, when privacy enhancement is initiated in such analtered PTZ type camera, the visual confirmation to an observer can besomewhat akin to an “eyeball rolling back in its socket.”

This mechanical privacy lens cap, shutter or mechanism can be activatedor deactivated automatically or manually, and locally or remotely. Forexample, in some implementations, the user can manually (e.g., usingtheir hands on the camera) initiate activation (closing or obscuring thelens) and deactivation (opening or making the lens visible) of theprivacy lens cap or shutter. Furthermore, this privacy lens cap orshutter system can be used on both wired and wireless cameras forprivacy enhancement purposes.

The technologies described herein can enable small, including wearable,form factors for wireless cameras that are operable for extended periodsof time. The described technologies can reduce power requirements forwireless camera implementations. As a result, smaller and/or lighterweight power supplies can power such wireless cameras. For example, thedescribed technologies can enable a wireless camera to have an earpiecesize form factor, e.g., similar to a Bluetooth headset for a mobilephone, and run on 4 or less miniature batteries such as hearing aidbatteries for 8 or more hours while producing high quality video at 30fps, e.g., VGA (640×480) or better video quality. In someimplementations, a wireless camera with an earpiece size form factor canhave dimensions of less than 3 by 1 by 1 inches. In someimplementations, the described technologies can enable a wireless camerato operate for five or more hours to capture and transmit video whiledrawing less than 50 milliwatts in average energy consumption.

In some implementations, a wireless camera can weigh less than 100 gramsas a result of using lighter batteries and the described technologies.In some implementations, a wireless camera can weigh less than 50 gramsas a result of using lighter batteries and the described technologies.In some implementations, a wireless camera can weigh less than 30 gramsas a result of using lighter batteries and the described technologies.In some implementations, a wireless camera can weigh less than 25 gramsas a result of using lighter batteries and the described technologies.Accordingly, the described technologies can enable implementations witha range of form factors and weights.

FIG. 7A shows an example of a computing system. A computer system caninclude a computer device 700. Computing device 700 is intended torepresent various forms of digital computers, such as laptops, desktops,workstations, personal digital assistants, servers, blade servers,mainframes, and other appropriate computers. The components shown here,their connections and relationships, and their functions, are meant tobe exemplary only, and are not meant to limit implementations of theinventions described and/or claimed in this document.

Computing device 700 can include a processor 702, memory 704, a storagedevice 706, a high-speed interface 708 connecting to memory 704 andhigh-speed expansion ports 710, and a low speed interface 712 connectingto low speed bus 714 and storage device 706. Each of the components 702,704, 706, 708, 710, and 712, are interconnected using various busses,and may be mounted on a common motherboard or in other manners asappropriate. The processor 702 can process instructions for executionwithin the computing device 700, including instructions stored in thememory 704 or on the storage device 706 to display graphical informationfor a GUI on an external input/output device, such as display 716coupled to high speed interface 708. In other implementations, multipleprocessors and/or multiple buses may be used, as appropriate, along withmultiple memories and types of memory. Also, multiple computing devices700 may be connected, with each device providing portions of thenecessary operations (e.g., as a server bank, a group of blade servers,or a multi-processor system).

The memory 704 stores information within the computing device 700. Inone implementation, the memory 704 is a computer-readable medium. In oneimplementation, the memory 704 is a volatile memory unit or units. Inanother implementation, the memory 704 is a non-volatile memory unit orunits.

The storage device 706 is capable of providing mass storage for thecomputing device 700. In one implementation, the storage device 706 is acomputer-readable medium. In various different implementations, thestorage device 706 may be a floppy disk device, a hard disk device, anoptical disk device, or a tape device, a flash memory or other similarsolid state memory device, or an array of devices, including devices ina storage area network or other configurations. In one implementation, acomputer program product is tangibly embodied in an information carrier.The computer program product contains instructions that, when executed,perform one or more methods, such as those described above. Theinformation carrier is a computer- or machine-readable medium, such asthe memory 704, the storage device 706, memory on processor 702, or apropagated signal.

The high speed controller 708 manages bandwidth-intensive operations forthe computing device 700, while the low speed controller 712 manageslower bandwidth-intensive operations. Such allocation of duties isexemplary only. In one implementation, the high-speed controller 708 iscoupled to memory 704, display 716 (e.g., through a graphics processoror accelerator), and to high-speed expansion ports 710, which may acceptvarious expansion cards (not shown). In the implementation, low-speedcontroller 712 is coupled to storage device 706 and low-speed expansionport 714. The low-speed expansion port, which may include variouscommunication ports (e.g., USB, Bluetooth, Ethernet, wireless Ethernet)may be coupled to one or more input/output devices, such as a keyboard,a pointing device, a scanner, or a networking device such as a switch orrouter, e.g., through a network adapter.

The computing device 700 may be implemented in a number of differentforms, as shown in the figure. For example, it may be implemented as astandard server 720, or multiple times in a group of such servers. Itmay also be implemented as part of a rack server system 724. Inaddition, it may be implemented in a personal computer such as a laptopcomputer 722. Alternatively, components from computing device 700 may becombined with other components in a mobile device (not shown), such asdevice 750. Each of such devices may contain one or more of computingdevice 700, 750, and an entire system may be made up of multiplecomputing devices 700, 750 communicating with each other.

FIG. 7B shows an example of a computing device. Computing device 750 isintended to represent various forms of mobile devices, such as personaldigital assistants, cellular telephones, smartphones, and other similarcomputing devices. The components shown here, their connections andrelationships, and their functions, are meant to be exemplary only, andare not meant to limit implementations of the inventions describedand/or claimed in this document. A computing device 750 can include aprocessor 752, memory 764, an input/output device such as a display 754,a communication interface 766, and a transceiver 768, among othercomponents. The device 750 may also be provided with a storage device,such as a microdrive or other device, to provide additional storage.Each of the components 750, 752, 764, 754, 766, and 768, areinterconnected using various buses, and several of the components may bemounted on a common motherboard or in other manners as appropriate.

The processor 752 can process instructions for execution within thecomputing device 750, including instructions stored in the memory 764.The processor may also include separate analog and digital processors.The processor may provide, for example, for coordination of the othercomponents of the device 750, such as control of user interfaces,applications run by device 750, and wireless communication by device750.

Processor 752 may communicate with a user through control interface 758and display interface 756 coupled to a display 754. The display 754 maybe, for example, a TFT LCD display or an OLED display, or otherappropriate display technology. The display interface 756 may compriseappropriate circuitry for driving the display 754 to present graphicaland other information to a user. The control interface 758 may receivecommands from a user and convert them for submission to the processor752. In addition, an external interface 762 may be provide incommunication with processor 752, so as to enable near areacommunication of device 750 with other devices. External interface 762may provide, for example, for wired communication (e.g., via a dockingprocedure) or for wireless communication (e.g., via Bluetooth or othersuch technologies).

The memory 764 stores information within the computing device 750. Inone implementation, the memory 764 is a computer-readable medium. In oneimplementation, the memory 764 is a volatile memory unit or units. Inanother implementation, the memory 764 is a non-volatile memory unit orunits. Expansion memory 774 may also be provided and connected to device750 through expansion interface 772, which may include, for example, aSIMM card interface. Such expansion memory 774 may provide extra storagespace for device 750, or may also store applications or otherinformation for device 750. Specifically, expansion memory 774 mayinclude instructions to carry out or supplement the processes describedabove, and may include secure information also. Thus, for example,expansion memory 774 may be provide as a security module for device 750,and may be programmed with instructions that permit secure use of device750. In addition, secure applications may be provided via the SIMMcards, along with additional information, such as placing identifyinginformation on the SIMM card in a non-hackable manner.

The memory may include for example, flash memory and/or MRAM memory, asdiscussed below. In one implementation, a computer program product istangibly embodied in an information carrier. The computer programproduct contains instructions that, when executed, perform one or moremethods, such as those described above. The information carrier is acomputer- or machine-readable medium, such as the memory 764, expansionmemory 774, memory on processor 752, or a propagated signal.

Device 750 may communicate wirelessly through communication interface766, which may include digital signal processing circuitry wherenecessary. Communication interface 766 may provide for communicationsunder various modes or protocols, such as GSM voice calls, SMS, EMS, orMMS messaging, CDMA, TDMA, PDC, WCDMA, CDMA2000, or GPRS, among others.Such communication may occur, for example, through radio-frequencytransceiver 768. In addition, short-range communication may occur, suchas using a Bluetooth, WiFi, or other such transceiver (not shown). Inaddition, GPS receiver module 770 may provide additional wireless datato device 750, which may be used as appropriate by applications runningon device 750.

Device 750 may also communication audibly using audio codec 760, whichmay receive spoken information from a user and convert it to usabledigital information. Audio codex 760 may likewise generate audible soundfor a user, such as through a speaker, e.g., in a handset of device 750.Such sound may include sound from voice telephone calls, may includerecorded sound (e.g., voice messages, music files, etc.) and may alsoinclude sound generated by applications operating on device 750.

The computing device 750 may be implemented in a number of differentforms, as shown in the figure. For example, it may be implemented as acellular telephone 780. It may also be implemented as part of asmartphone 782, personal digital assistant, or other similar mobiledevice.

Where appropriate, the systems and the functional operations describedin this specification can be implemented in digital electroniccircuitry, or in computer software, firmware, or hardware, including thestructural means disclosed in this specification and structuralequivalents thereof, or in combinations of them. The techniques can beimplemented as one or more computer program products, i.e., one or morecomputer programs tangibly embodied in an information carrier, e.g., ina machine readable storage device or in a propagated signal, forexecution by, or to control the operation of, data processing apparatus,e.g., a programmable processor, a computer, or multiple computers. Acomputer program (also known as a program, software, softwareapplication, or code) can be written in any form of programminglanguage, including compiled or interpreted languages, and it can bedeployed in any form, including as a stand alone program or as a module,component, subroutine, or other unit suitable for use in a computingenvironment. A computer program does not necessarily correspond to afile. A program can be stored in a portion of a file that holds otherprograms or data, in a single file dedicated to the program in question,or in multiple coordinated files (e.g., files that store one or moremodules, sub programs, or portions of code). A computer program can bedeployed to be executed on one computer or on multiple computers at onesite or distributed across multiple sites and interconnected by acommunication network.

The processes and logic flows described in this specification can beperformed by one or more programmable processors executing one or morecomputer programs to perform the described functions by operating oninput data and generating output. The processes and logic flows can alsobe performed by, and apparatus can be implemented as, special purposelogic circuitry, e.g., an FPGA (field programmable gate array) or anASIC (application specific integrated circuit).

Processors suitable for the execution of a computer program include, byway of example, both general and special purpose microprocessors, andany one or more processors of any kind of digital computer. Generally,the processor will receive instructions and data from a read only memoryor a random access memory or both. The essential elements of a computerare a processor for executing instructions and one or more memorydevices for storing instructions and data. Generally, a computer willalso include, or be operatively coupled to receive data from or transferdata to, or both, one or more mass storage devices for storing data,e.g., magnetic, magneto optical disks, or optical disks. Informationcarriers suitable for embodying computer program instructions and datainclude all forms of non volatile memory, including by way of examplesemiconductor memory devices, e.g., EPROM, EEPROM, and flash memorydevices; magnetic disks, e.g., internal hard disks or removable disks;magneto optical disks; and CD ROM and DVD-ROM disks. The processor andthe memory can be supplemented by, or incorporated in, special purposelogic circuitry.

To provide for interaction with a user, aspects of the describedtechniques can be implemented on a computer having a display device,e.g., a CRT (cathode ray tube) or LCD (liquid crystal display) monitor,for displaying information to the user and a keyboard and a pointingdevice, e.g., a mouse or a trackball, by which the user can provideinput to the computer. Other kinds of devices can be used to provide forinteraction with a user as well; for example, feedback provided to theuser can be any form of sensory feedback, e.g., visual feedback,auditory feedback, or tactile feedback; and input from the user can bereceived in any form, including acoustic, speech, or tactile input.

The techniques can be implemented in a computing system that includes aback-end component, e.g., as a data server, or that includes amiddleware component, e.g., an application server, or that includes afront-end component, e.g., a client computer having a graphical userinterface or a Web browser through which a user can interact with animplementation, or any combination of such back-end, middleware, orfront-end components. The components of the system can be interconnectedby any form or medium of digital data communication, e.g., acommunication network. Examples of communication networks includepoint-to-point connections such as universal serial bus (USB) devices orUSB hubs, a local area network (“LAN”), and a wide area network (“WAN”),e.g., the Internet.

The computing system can include clients and servers. A client andserver are generally remote from each other and typically interactthrough a communication network. The relationship of client and serverarises by virtue of computer programs running on the respectivecomputers and having a client-server relationship to each other.

While operations are depicted in the drawings in a particular order,this should not be understood as requiring that such operations beperformed in the particular order shown or in sequential order, or thatall illustrated operations be performed, to achieve desirable results.In certain circumstances, multitasking and parallel processing may beadvantageous. Moreover, the separation of various system components inthe embodiments described above should not be understood as requiringsuch separation in all embodiments, and it should be understood that thedescribed program components and systems can generally be integratedtogether in a single software product or packaged into multiple softwareproducts.

A number of embodiments have been described. Nevertheless, it will beunderstood that various modifications may be made without departing fromthe spirit and scope of the described embodiments. For example, thetriggering events (e.g., motion, sound, infrared detection) describedabove can be used to further lower the power consumption of the wirelesscamera. In many situations video surveillance cameras are placed inareas where there is very little motion for many hours. In these cases,significant energy savings can be gained by reducing the rate of any orall of the following functions: image capture, image compression, imagetransmission, based on a determination that motion has ceased.

In some implementations, the motion detection can use an external sensoror can be achieved by an algorithm that carries out an analysis ofchanges between captured images. The algorithm can be implemented in thecamera, or in the base station. In some cases, the motion detectionprocessing can be distributed between the camera and the base station.In the case where parts or the entire algorithm is implemented in thebase station, information regarding the motion sensing processing can betransferred to the camera by a secondary, low bandwidth radio link. Anexample of such an algorithm can be found in “BayesianIllumination-Invariant Motion Detection” by Til Aach and Lutz Dumbgenand Rudolf Mester and Daniel Toth, as described in Vol. III pages640-643 of Proceedings IEEE International Conference on Image Processing(ICIP).

For example, suppose that a wireless video surveillance camera, asdescribed above, is in a fast image capturing mode. This means that thewireless camera is capturing, compressing, and transmitting images at ahigh capture rate. A motion detection algorithm can be used to processesthe captured image data to determine if there has been motion in thefield of view. If at any time the motion detection algorithm determinesthat there is no motion in the field of view (based on a certainthreshold level of probability and criteria), then the camera can entera slow capture mode and a period of slower capture rate can beinitiated.

On the other hand, if the motion detection algorithm determines thatmotion persists in the field of view, the wireless network camera systemcontinues to capture images at the higher rate. Similarly, during a slowcapture mode, the motion detection algorithm can be used to initiate afast capture mode if motion has been detected.

The amount of energy saving based on the motion detection can beillustrated by analyzing a specific example camera system. Suppose thatfor a specific camera system, during the fast capture mode the cameraoperates at 3 frames per second (fps) and consumes 2 mJ per frame.Therefore, the average power dissipation during this fast capture modeis 3 fps×2 mJ per frame=6 mW. Suppose that during the slow capture modethe camera captures one frame every 5 seconds (0.2 fps) and consumes 1.5mJ per frame. Therefore, the average power dissipation during this slowcapture mode is 0.2 fps×1.5 mJ per frame=0.3 mW.

Further suppose that motion is detected 20% of the time overall. Thenthe sustained average power consumption of the camera in operation willbe (20%×6+80%×0.3)=1.44 mW. This is clearly lower power then if thecamera were operating in the fast capture mode continuously, which canlead to a sustained average power dissipation of 6 mW during cameraoperation.

In some implementations, the motion detection algorithm can be performedin the base station, and significant power saving benefits can beachieved because the camera is not used to carry out potentiallypower-intensive and complex algorithms. In addition, complex andcomprehensive algorithms or video analytics can be performed because thebase station can have access to more power and more computationalresources. In this manner, detection of additional triggering eventsbeyond simple motion and other categories such as object recognition canbe achieved. These more comprehensive and complex algorithms can havethe potential benefit of increasing the accuracy and reliability of thetriggering event detection and reducing probability of false detectionsor missing activity, objects or events. Examples of these types ofalgorithms can be seen in, for example, software products like Xprotectfrom the Milestone Systems A/S Corporation.

In some implementations, the base station can initiate user alerts suchas automated cellular phone text messages, phone calls, emails and othertextual, visual, or auditory alerts to the user based on a triggeringevent. The triggering event can be initiated as a result of motiondetection through ultrasonic, infrared, acoustic or electricalswitch/relay tripping. The triggering event can also be based on thevideo image processing described above. This message alert capabilitycan avoid the need for the user to constantly monitor the video streamfor a triggering event.

In some implementations, the base station can alter the image capturerate in response to information or control data from a client devicewhich is pulling images from the base station. For example, the clientmay distinguish between “active user observation” mode or“automatic/passive image capture” mode. During the “active userobservation mode,” the base station can receive information from aclient based on the fact that a user (human observer) is activelymonitoring or wishes to monitor the video stream. This information orcontrol data can be communicated to the base station and cause the basestation to increase the frame capture rate. During the“automatic/passive image capture mode,” the base station can receiveinformation or control data from the client because a network digitalvideo recording or other process is responsible for requesting images.Additionally, the base station can automatically determine the imagecapture rate based on activity or triggers detected by the camera or thebase station itself. This detection of motion, or an object of interest,or a trigger activity can cause the base station to decrease the rate ofimage capture. Accordingly, other embodiments are within the scope ofthe following claims.

While this specification contains many specifics, these should not beconstrued as limitations on the scope of the invention or of what may beclaimed, but rather as descriptions of features specific to particularembodiments of the invention. Certain features that are described inthis specification in the context of separate embodiments can also beimplemented in combination in a single embodiment. Conversely, variousfeatures that are described in the context of a single embodiment canalso be implemented in multiple embodiments separately or in anysuitable subcombination. Moreover, although features may be describedabove as acting in certain combinations and even initially claimed assuch, one or more features from a claimed combination can in some casesbe excised from the combination, and the claimed combination may bedirected to a subcombination or variation of a subcombination.

The invention claimed is:
 1. A wearable form factor wireless cameracomprising: an image sensor operatively coupled to a low power infrareddetection module, the image sensor configured to capture one or morehours of infrared video; wherein the low power infrared detection moduleand the image sensor are powered by a battery; wherein the image sensor,the low power infrared detection module and the battery are internal tothe wearable form factor wireless camera; wherein the wearable formfactor wireless camera is configured to attach to clothing worn on auser and is ruggedized; a storage device operatively coupled to the lowpower infrared detection module and the image sensor and powered by thebattery, the storage device configured to store the captured one or morehours of infrared video at a first fidelity; wherein the storage deviceis internal to the wearable form factor wireless camera; wherein thestored one or more hours of infrared video is capable of beingtransmitted at the first fidelity and at a second fidelity; wherein thefirst fidelity provides a higher frame rate than the second fidelity;and a burst transmission unit operatively coupled to the storage deviceand powered by the battery, the burst transmission unit configured totransmit the stored one or more hours of infrared video at the secondfidelity via a cellular network; wherein the burst transmission unit isinternal to the wearable form factor wireless camera.
 2. The wearableform factor wireless camera of claim 1, further comprising: a processoroperatively coupled to the storage device, a buffering memory and theburst transmission unit, and powered by the battery, the processorconfigured to switch the burst transmission unit from transmission ofthe stored one or more hours of infrared video at the second fidelity totransmission of the stored one or more hours of infrared video at thefirst fidelity upon an occurrence of a trigger event; wherein theprocessor and the buffering memory are internal to the wearable formfactor wireless camera; and the burst transmission unit furtherconfigured to transmit the stored one or more hours of infrared video atthe first fidelity via the cellular network.
 3. The wearable form factorwireless camera of claim 2, wherein the trigger event includes aninfrared motion detection, a sound detection, an ultrasonic detection, arelay switch, a micro switch, radio signaling circuitry or a user input.4. The wearable form factor wireless camera of claim 2, wherein the lowpower infrared detection module triggers the trigger event.
 5. Thewearable form factor wireless camera of claim 1, wherein the low powerinfrared detection module includes a pyroelectric infrared sensor. 6.The wearable form factor wireless camera of claim 1, wherein the lowpower infrared detection module includes a passive infrared (PIR)detector.
 7. The wearable form factor wireless camera of claim 1,wherein the wearable form factor wireless camera pulses a highlyefficient infrared light emitting diode (LED) synchronized to an imagecapture frequency and phase.
 8. The wearable form factor wireless cameraof claim 1, wherein the burst transmission unit of the wearable formfactor wireless camera comprises multiple output circuits withrespective different power amplifier bias settings, wherein each of theoutput circuits comprise a power amplifier and antenna matchingcircuitry.
 9. The wearable form factor wireless camera of claim 1,wherein the battery is a low voltage hearing aid battery.
 10. Thewearable form factor wireless camera of claim 1, wherein the batterypowers the wearable form factor wireless camera for eight (8) or morehours.
 11. The wearable form factor wireless camera of claim 1, whereinthe first fidelity provides a frame rate of thirty (30) or more framesper second (fps).
 12. A method, in a wearable form factor wirelesscamera, of video delivery, the method comprising: capturing, by an imagesensor operatively coupled to a low power infrared detection module, oneor more hours of infrared video; wherein the low power infrareddetection module and the image sensor are powered by a battery; whereinthe image sensor, the low power infrared detection module and thebattery are internal to the wearable form factor wireless camera;wherein the wearable form factor wireless camera is capable of attachingto clothing worn on a user and is ruggedized; storing, by a storagedevice operatively coupled to the low power infrared detection moduleand the image sensor and powered by the battery, the captured one ormore hours of infrared video at a first fidelity; wherein the storagedevice is internal to the wearable form factor wireless camera; whereinthe stored one or more hours of infrared video is capable of beingtransmitted at the first fidelity and at a second fidelity; wherein thefirst fidelity provides a higher frame rate than the second fidelity;and transmitting, via a cellular network by a burst transmission unitoperatively coupled to the storage device and powered by the battery,the stored one or more hours of infrared video at the second fidelity;wherein the burst transmission unit is internal to the wearable formfactor wireless camera.
 13. The method of claim 12, further comprising:switching, by a processor operatively coupled to the storage device, abuffering memory and the burst transmission unit, and powered by thebattery, the burst transmission unit from transmission of the stored oneor more hours of infrared video at the second fidelity to transmissionof the stored one or more hours of infrared video at the first fidelityupon an occurrence of a trigger event; wherein the processor and thebuffering memory are internal to the wearable form factor wirelesscamera; and transmitting, via the cellular network by the bursttransmission unit, the stored one or more hours of infrared video at thefirst fidelity.
 14. The method of claim 13, wherein the trigger eventincludes an infrared motion detection, a sound detection, an ultrasonicdetection, a relay switch, a micro switch, radio signaling circuitry ora user input.
 15. The method of claim 13, wherein the low power infrareddetection module triggers the trigger event.
 16. The method of claim 12,wherein the low power infrared detection module includes a pyroelectricinfrared sensor.
 17. The method of claim 12, wherein the low powerinfrared detection module includes a passive infrared (PIR) detector.18. The method of claim 12, wherein the wearable form factor wirelesscamera pulses a highly efficient infrared light emitting diode (LED)synchronized to an image capture frequency and phase.
 19. The method ofclaim 12, wherein the first fidelity provides a frame rate of thirty(30) or more frames per second (fps).